U.S. patent application number 12/417723 was filed with the patent office on 2009-12-17 for carbohydrates.
This patent application is currently assigned to XYLECO, INC.. Invention is credited to Marshall MEDOFF.
Application Number | 20090312537 12/417723 |
Document ID | / |
Family ID | 40886420 |
Filed Date | 2009-12-17 |
United States Patent
Application |
20090312537 |
Kind Code |
A1 |
MEDOFF; Marshall |
December 17, 2009 |
CARBOHYDRATES
Abstract
Carbohydrates having functional groups, such as carboxylic acid
groups and methods of making such carbohydrates.
Inventors: |
MEDOFF; Marshall;
(Brookline, MA) |
Correspondence
Address: |
Xyleco, Inc.
2682 N.W. Shields Dr.
Bend
OR
97701
US
|
Assignee: |
XYLECO, INC.
Woburn
MA
|
Family ID: |
40886420 |
Appl. No.: |
12/417723 |
Filed: |
April 3, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61073530 |
Jun 18, 2008 |
|
|
|
61049405 |
Apr 30, 2008 |
|
|
|
61073674 |
Jun 18, 2008 |
|
|
|
61139453 |
Dec 19, 2008 |
|
|
|
Current U.S.
Class: |
536/63 ;
536/123.1; 536/124; 536/56 |
Current CPC
Class: |
C08B 15/06 20130101;
D21C 3/02 20130101; C10L 5/44 20130101; C08B 15/04 20130101; Y02E
50/30 20130101; D21C 9/001 20130101; C08H 8/00 20130101; D21C 5/00
20130101; D21C 3/22 20130101; Y02E 50/10 20130101 |
Class at
Publication: |
536/63 ;
536/123.1; 536/56; 536/124 |
International
Class: |
C08B 1/00 20060101
C08B001/00; C08B 37/00 20060101 C08B037/00; C08B 3/00 20060101
C08B003/00 |
Claims
1. A material comprising a plurality of saccharide units arranged
in a molecular chain, wherein from about 1 out of every 2 to about
1 out of every 250 saccharide units comprises a carboxylic acid
group, or an ester or salt thereof, wherein the number of
carboxylic acid groups is determined by titration.
2. The material of claim 1, wherein the material includes a
plurality of said molecular chains.
3. The material of claim 2, wherein each chain comprises
hemicellulose or cellulose.
4. The material of claim 1, wherein from about 1 out of every 5 to
about 1 out of every 250 saccharide units of each chain comprises a
carboxylic acid group, or an ester or salt thereof.
5. The material of claim 1, wherein from about 1 out of every 8 to
about 1 out of every 100 saccharide units of each chain comprises a
carboxylic acid group, or an ester or salt thereof.
6. The material of claim 1, wherein from about 1 out of every 10 to
about 1 out of every 50 saccharide units of each chain comprise a
carboxylic acid group, or an ester or salt thereof.
7. The material of claim 1, wherein the material comprise a
cellulosic or lignocellulosic material.
8. The material of claim 1, wherein the saccharide units comprise 5
or 6 carbon saccharide units.
9. The material of claim 1, wherein each chain has between about 10
and about 200 saccharide units, e.g., between about 10 and about
100 or between about 10 and about 50.
10. The material of claim 1, wherein the average molecular weight
of the material relative to PEG standards is from about 1,000 to
about 1,000,000, wherein the molecular weight is determined using
GPC, utilizing a saturated solution (8.4% by weight) of lithium
chloride (LiCl) in dimethyl acetamide (DMAc) as the mobile
phase.
11. The material of claim 1, wherein the average molecular weight
of the material relative to PEG standards is less than about
10,000.
12. A method of providing a functionalized carbohydrate, the method
comprising: treating a base material comprising a carbohydrate
comprising a plurality of saccharide units with accelerated
particles in an oxidizing environment to provide a functionalized
carbohydrate in which from about 1 out of every 2 to about 1 out of
every 250 saccharide units comprise a carboxylic acid group.
13. A method of providing a functionalized carbohydrate, the method
comprising: treating a base material comprising a carbohydrate
comprising a plurality of saccharide units with accelerated
particles to provide a functionalized carbohydrate in which from
about 1 out of every 5 to about 1 out of every 1500 saccharide
units comprise a nitroso, nitro, or nitrile group.
14. A material comprising a plurality of saccharide units arranged
in a molecular chain, wherein from about 1 out of every 5 to about
1 out of every 1500 saccharide units comprises a nitroso, nitro, or
nitrile group.
15. The material of claim 14, wherein the material includes a
plurality of said molecular chains.
16. The material of claim 15, wherein each chain comprises
hemicellulose or cellulose.
17. The material of claim 14, wherein from about 1 out of every 10
to about 1 out of every 1000 saccharide units of each chain
comprises a nitroso, nitro, or nitrile group.
18. The material of claim 14, wherein from about 1 out of every 35
to about 1 out of every 750 saccharide units of each chain
comprises a nitroso, nitro, or nitrile group.
19. The material of claim 14, wherein the material comprises a
mixture of nitrile groups and carboxylic acid groups.
20. The material of claim 14, wherein the material comprises a
cellulosic or lignocellulosic material.
21. The material of claim 14, wherein the saccharide units comprise
5 or 6 carbon saccharide units.
22. The material of claim 14, wherein each chain has between about
10 and about 200 saccharide units, e.g., between about 10 and about
100 or between about 10 and about 50.
23. The material of claim 14, wherein the average molecular weight
of the material relative to PEG standards is from about 1,000 to
about 1,000,000, wherein the molecular weight is determined using
GPC, utilizing a saturated solution (8.4% by weight) of lithium
chloride (LiCl) in dimethyl acetamide (DMAc) as the mobile
phase.
24. The material of claim 14, wherein the average molecular weight
of the material relative to PEG standards is less than about
10,000.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. Nos. 61/049,405, filed Apr. 30, 2008, 61/073,530,
filed Jun. 18, 2008, 61/073,674, filed Jun. 18, 2008, and
61/139,453, filed Dec. 19, 2008. The full disclosure of each of
these provisional applications is incorporated herein by
reference.
BACKGROUND
[0002] Various carbohydrates, such as cellulosic and
lignocellulosic materials, e.g., in fibrous form, are produced,
processed, and used in large quantities in a number of
applications. Often such materials are used once, and then
discarded as waste, or are simply considered to be waste materials,
e.g., sewage, bagasse, sawdust, and stover.
SUMMARY
[0003] Biomass can be processed to alter its structure at one more
levels. The processed biomass can then be used as source of
materials and fuel.
[0004] Many embodiments of this application use Natural Force.TM.
Chemistry. Natural Force Chemistry methods use the controlled
application and manipulation of physical forces, such as particle
beams, gravity, light, etc., to create intended structural and
chemical molecular change. In preferred implementations, Natural
Force.TM. Chemistry methods alter molecular structure without
chemicals or microorganisms. By applying the processes of Nature,
new useful matter can be created without harmful environmental
interference.
[0005] Carbohydrate-containing materials (e.g., biomass materials
or biomass-derived materials, such as starchy materials, cellulosic
materials or lignocellulosic materials) can be treated and
processed. In some instances, the carbohydrates described herein
are more soluble, e.g., in water, and are more readily utilized by
microorganisms, e.g., during fermentation, in comparison to native
carbohydrates, e.g., in their natural state. In addition, many of
the carbohydrate materials described herein can be less prone to
oxidation and can have enhanced long-term stability (e.g., to
oxidation in air under ambient conditions).
[0006] In one aspect, the invention features materials including a
plurality of saccharide units arranged in a molecular chain. From
about 1 out of every 2 to about 1 out of every 250 saccharide units
includes a carboxylic acid group, or an ester or salt thereof. In
another aspect, materials include a plurality of such molecular
chains.
[0007] In some embodiments, from about 1 out of every 5 to about 1
out of every 250 saccharide units of each chain includes a
carboxylic acid group, or an ester or salt thereof. For example,
about 1 out of every 8 to about 1 out of every 100 saccharide units
of each chain includes a carboxylic acid group, or an ester or salt
thereof In another aspect, about 1 out of every 10 to about 1 out
of every 50 saccharide units of each chain includes a carboxylic
acid group, or an ester or salt thereof.
[0008] The materials can include, for example, di- or
tri-saccharides, or polymeric saccharides.
[0009] In some embodiments, materials include a cellulosic or
lignocellulosic material.
[0010] In some embodiments, the saccharide units include 5 or 6
carbon saccharide units. In another embodiment, each chain can have
between about 10 and about 200 saccharide units, e.g., between
about 10 and about 100 or between about 10 and about 50. For
example, each chain includes hemicellulose or cellulose.
[0011] In some embodiments, the average molecular weight of the
materials relative to PEG standards can be from about 1,000 to
about 1,000,000, such as between 1,500 and 200,000 or 2,000 and
10,000. For example, the average molecular weight of the materials
relative to PEG standards can be less than about 10,000. In some
embodiments, of all carbohydrate in the material, at least 10, 25,
50, 75, 80, 90, 95, or 98% of the carbohydrate has one or more of
the above properties. Also featured is a preparation of such
carbohydrate that is at least 50, 80, 90, 95, 98, or 99% pure.
[0012] In some embodiments, each chain also includes saccharide
units that include nitroso, nitro, or nitrile groups.
[0013] In some embodiments, the material has a low moisture
content, e.g., less than about 7.5, 5, 3, 2.5, 2, 1.5, 1, or 0.5%
percent water by weight.
[0014] In another aspect, the invention features methods of
providing functionalized carbohydrates that include providing a
base material that includes a carbohydrate that includes a
plurality of saccharide units; and treating the base material with
accelerated particles in an oxidizing environment to provide a
functionalized carbohydrate in which from about 1 out of every 2 to
about 1 out of every 250 saccharide units include a carboxylic acid
group.
[0015] In some embodiments, the base material is irradiated.
Radiation may be applied from a device that is in a vault.
[0016] The term "fibrous material," as used herein, is a material
that includes numerous loose, discrete and separable fibers. For
example, a fibrous material can be prepared from a bleached Kraft
paper fiber source by shearing, e.g., with a rotary knife
cutter.
[0017] The term "screen," as used herein, means a member capable of
sieving material according to size. Examples of screens include a
perforated plate, cylinder or the like, or a wire mesh or cloth
fabric.
[0018] The term "plant biomass" and "lignocellulosic biomass" refer
to virtually any plant-derived organic matter (woody or non-woody)
available for energy on a sustainable basis.
[0019] Plant biomass can include, but is not limited to,
agricultural or food crops (e.g., sugarcane, sugar beets or corn
kernels) or an extract therefrom (e.g., sugar from sugarcane and
corn starch from corn), agricultural crop wastes and residues such
as corn stover, wheat straw, rice straw, sugar cane bagasse, and
the like. Plant biomass further includes, but is not limited to,
trees, woody energy crops, wood wastes and residues such as
softwood forest thinnings, barky wastes, sawdust, paper and pulp
industry waste streams, wood fiber, and the like. Additionally
grass crops, such as switchgrass and the like have potential to be
produced on a large-scale as another plant biomass source. For
urban areas, the best potential plant biomass feedstock includes
yard waste (e.g., grass clippings, leaves, tree clippings, and
brush) and vegetable processing waste. Plant biomass also includes
aquatic biomass such as algae and seaweed.
[0020] "Lignocellulosic feedstock," is any type of plant biomass
such as, but not limited to, non-woody plant biomass, cultivated
crops, such as, but not limited to, grasses, for example, but not
limited to, C4 grasses, such as switchgrass, cord grass, rye grass,
miscanthus, reed canary grass, or a combination thereof, or sugar
processing residues such as bagasse, or beet pulp, agricultural
residues, for example, soybean stover, corn stover, rice straw,
rice hulls, barley straw, corn cobs, wheat straw, canola straw,
rice straw, oat straw, oat hulls, corn fiber, recycled wood pulp
fiber, sawdust, hardwood, for example aspen wood and sawdust,
softwood, or a combination thereof Further, the lignocellulosic
feedstock may include cellulosic waste material such as, but not
limited to, newsprint, cardboard, sawdust, and the like.
[0021] Lignocellulosic feedstock may include one species of fiber
or alternatively, lignocellulosic feedstock may include a mixture
of fibers that originate from different lignocellulosic feedstocks.
Furthermore, the lignocellulosic feedstock may comprise fresh
lignocellulosic feedstock, partially dried lignocellulosic
feedstock, fully dried lignocellulosic feedstock or a combination
thereof.
[0022] For the purposes of this disclosure, carbohydrates are
materials that are composed entirely of one or more saccharide
units or that include one or more saccharide units. Carbohydrates
can be part of a supramolecular structure, e.g., covalently bonded
into the structure. Examples of such materials include
lignocellulosic materials, such as found in wood.
[0023] A "sheared material," as used herein, is a material that
includes discrete fibers in which at least about 50% of the
discrete fibers, have a length/diameter (L/D) ratio of at least
about 5, and that has an uncompressed bulk density of less than
about 0.6 g/cm.sup.3. A sheared material is thus different from a
material that has been cut, chopped or ground.
[0024] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, suitable methods and materials are described below. All
publications, patent applications, patents, and other references
mentioned herein are incorporated by reference in their entirety.
In case of conflict, the present specification, including
definitions, will control. In addition, the materials, methods, and
examples are illustrative only and not intended to be limiting. All
patents, patent applications and publications referenced herein are
incorporated herein by reference in their entireties.
[0025] This application incorporates by reference herein the entire
contents of International Application No. PCT/US2007/022719, filed
on Oct. 26, 2007. The full disclosures of each of the following
U.S. patent applications, which are being filed concurrently
herewith, are hereby incorporated by reference herein: Attorney
Docket Nos. 08995-0062001, 08895-0063001, 08895-0070001,
08895-0073001, 08895-0075001, 08895-0076001, 08895-0085001,
08895-0096001, and 08895-0103001.
[0026] Other features and advantages of the invention will be
apparent from the following detailed description, and from the
claims.
DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is block diagram illustrating conversion of a fiber
source into a first and second fibrous material.
[0028] FIG. 2 is a cross-sectional view of a rotary knife
cutter.
[0029] FIG. 3 is block diagram illustrating conversion of a fiber
source into a first, second and third fibrous material.
[0030] FIG. 4 is a block diagram illustrating a treatment sequence
for processing feedstock.
[0031] FIG. 5 is a perspective, cut-away view of a gamma irradiator
housed in a concrete vault.
[0032] FIG. 6 is an enlarged perspective view of region R of FIG.
9.
[0033] FIG. 7 is a schematic representation of biomass being
ionized, and then oxidized or quenched.
[0034] FIG. 8 is a scanning electron micrograph of a fibrous
material produced from polycoated paper at 25.times. magnification.
The fibrous material was produced on a rotary knife cutter
utilizing a screen with 1/8 inch openings.
[0035] FIG. 9 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was produced on a rotary knife
cutter utilizing a screen with 1/8 inch openings.
[0036] FIG. 10 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was twice sheared on a rotary
knife cutter utilizing a screen with 1/16 inch openings during each
shearing.
[0037] FIG. 11 is a scanning electron micrograph of a fibrous
material produced from bleached Kraft board paper at 25.times.
magnification. The fibrous material was thrice sheared on a rotary
knife cutter. During the first shearing, a 1/8 inch screen was
used; during the second shearing, a 1/16 inch screen was used, and
during the third shearing a 1/32 inch screen was used.
[0038] FIG. 12 is an infrared spectrum of Kraft board paper sheared
on a rotary knife cutter.
[0039] FIG. 13 is an infrared spectrum of the Kraft paper of FIG.
12 after irradiation with 100 Mrad of gamma radiation.
[0040] FIG. 14 is a .sup.13C-NMR of sample P-100e with a delay time
of 1 minute between pulses.
DETAILED DESCRIPTION
[0041] Functionalized carbohydrates having desired types and
amounts of functionality, such as carboxylic acid groups, nitrile
groups, nitro groups, or nitroso groups, can be prepared using the
methods described herein. Such functionalized carbohydrates can be
more soluble, easier to utilize by various microorganisms during
fermentation or can be more stable over the long term.
Types of Biomass
[0042] Generally, any biomass material that includes carbohydrates
composed entirely of one or more saccharide units or that include
one or more saccharide units can be processed by any of the methods
described herein. For example, the biomass material can be
cellulosic or lignocellulosic materials, starchy materials, such as
kernels of corn, grains of rice or other foods, or materials that
are or that include one or more low molecular weight sugars, such
as sucrose or cellobiose.
[0043] For example, such materials can include paper, paper
products, wood, wood-related materials, particle board, grasses,
rice hulls, bagasse, cotton, jute, hemp, flax, bamboo, sisal,
abaca, straw, corn cobs, rice hulls, coconut hair, algae, seaweed,
cotton, synthetic celluloses, or mixtures of any of these.
[0044] Fiber sources include cellulosic fiber sources, including
paper and paper products (e.g., polycoated paper and Kraft paper),
and lignocellulosic fiber sources, including wood, and wood-related
materials, e.g., particleboard. Other suitable fiber sources
include natural fiber sources, e.g., grasses, rice hulls, bagasse,
cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs,
rice hulls, coconut hair; fiber sources high in .alpha.-cellulose
content, e.g., cotton; and synthetic fiber sources, e.g., extruded
yarn (oriented yarn or un-oriented yarn). Natural or synthetic
fiber sources can be obtained from virgin scrap textile materials,
e.g., remnants or they can be post consumer waste, e.g., rags. When
paper products are used as fiber sources, they can be virgin
materials, e.g., scrap virgin materials, or they can be
post-consumer waste. Aside from virgin raw materials,
post-consumer, industrial and processing waste (e.g., effluent from
paper processing) can also be used as fiber sources. Also, the
fiber source can be obtained or derived from human (e.g., sewage),
animal or plant wastes. Additional fiber sources have been
described in U.S. Pat. Nos. 6,448,307, 6,258,876, 6,207,729,
5,973,035 and 5,952,105.
[0045] In some embodiments, the carbohydrate is or includes a
material having one or more .beta.-1,4-linkages and having a number
average molecular weight between about 3,000 and 50,000. Such a
carbohydrate is or includes cellulose (I), which is derived from
(.beta.-glucose 1) through condensation of
.beta.(1.fwdarw.4)-glycosidic bonds. This linkage contrasts itself
with that for .alpha.(1.fwdarw.4)-glycosidic bonds present in
starch and other carbohydrates.
##STR00001##
[0046] Starchy materials include starch itself, e.g., corn starch,
wheat starch, potato starch or rice starch, a derivative of starch,
or a material that includes starch, such as an edible food product
or a crop. For example, the starchy material can be arracacha,
buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum,
regular household potatoes, sweet potato, taro, yams, or one or
more beans, such as favas, lentils or peas. Blends of any one or
more starchy materials are also a starchy material. In particular
embodiments, the starchy material is derived from corn. Various
corn starches and derivatives are described in "Corn Starch," Corn
Refiners Association (11.sup.th Edition, 2006).
[0047] Biomass materials that include low molecular weight sugars
can, e.g., include at least about 0.5 percent by weight of the low
molecular sugar, e.g., at least about 2, 3, 4, 5, 6, 7, 8, 9, 10,
12.5, 25, 35, 50, 60, 70, 80, 90 or even at least about 95 percent
by weight of the low molecular weight sugar. In some instances, the
biomass is composed substantially of the low molecular weight
sugar, e.g., greater than 95 percent by weight, such as 96, 97, 98,
99 or substantially 100 percent by weight of the low molecular
weight sugar.
Feedstock Preparation
[0048] In some cases, methods of processing begin with a physical
preparation of the feedstock, e.g., size reduction of raw feedstock
materials, such as by cutting, grinding, shearing or chopping. In
some cases, loose feedstock (e.g., recycled paper, starchy
materials, or switchgrass) is prepared by shearing or shredding.
Screens and/or magnets can be used to remove oversized or
undesirable objects such as, for example, rocks or nails from the
feed stream.
[0049] Feed preparation systems can be configured to produce feed
streams with specific characteristics such as, for example,
specific maximum sizes, specific length-to-width, or specific
surface areas ratios. As a part of feed preparation, the bulk
density of feedstocks can be controlled (e.g., increased or
decreased).
Size Reduction
[0050] In some embodiments, the material to be processed is in the
form of a fibrous material that includes fibers provided by
shearing a fiber source. For example, the shearing can be performed
with a rotary knife cutter.
[0051] For example, and by reference to FIG. 1, a fiber source 210
is sheared, e.g., in a rotary knife cutter, to provide a first
fibrous material 212. The first fibrous material 212 is passed
through a first screen 214 having an average opening size of 1.59
mm or less ( 1/16 inch, 0.0625 inch) to provide a second fibrous
material 216. If desired, the fiber source can be cut prior to the
shearing, e.g., with a shredder. For example, when a paper is used
as the fiber source, the paper can be first cut into strips that
are, e.g., 1/4- to 1/2-inch wide, using a shredder, e.g., a
counter-rotating screw shredder, such as those manufactured by
Munson (Utica, N.Y). As an alternative to shredding, the paper can
be reduced in size by cutting to a desired size using a guillotine
cutter. For example, the guillotine cutter can be used to cut the
paper into sheets that are, e.g., 10 inches wide by 12 inches
long.
[0052] In some embodiments, the shearing of fiber source and the
passing of the resulting first fibrous material through the first
screen are performed concurrently. The shearing and the passing can
also be performed in a batch-type process.
[0053] For example, a rotary knife cutter can be used to
concurrently shear the fiber source and screen the first fibrous
material. Referring to FIG. 2, a rotary knife cutter 220 includes a
hopper 222 that can be loaded with a shredded fiber source 224.
Shredded fiber source 224 is sheared between stationary blades 230
and rotating blades 232 to provide a first fibrous material 240.
First fibrous material 240 passes through screen 242, and the
resulting second fibrous material 244 is captured in bin 250. To
aid in the collection of the second fibrous material, the bin can
have a pressure below nominal atmospheric pressure, e.g., at least
10 percent below nominal atmospheric pressure, e.g., at least 25
percent below nominal atmospheric pressure, at least 50 percent
below nominal atmospheric pressure, or at least 75 percent below
nominal atmospheric pressure. In some embodiments, a vacuum source
252 is utilized to maintain the bin below nominal atmospheric
pressure.
[0054] Shearing can be advantageous for "opening up" and
"stressing" the fibrous materials, making the cellulose of the
materials more susceptible to chain scission and/or reduction of
crystallinity. The open materials can also be more susceptible to
oxidation when irradiated in an oxidizing environment. In addition,
shearing generally makes a low bulk density material that can be
deeply penetrated with a beam of electrons.
[0055] The fiber source can be sheared in a dry state, a hydrated
state (e.g., having up to ten percent by weight absorbed water), or
in a wet state, e.g., having between about 10 percent and about 75
percent by weight water. The fiber source can even be sheared while
partially or fully submerged under a liquid, such as water,
ethanol, isopropanol.
[0056] The fiber source can also be sheared under a gas (such as a
stream or atmosphere of gas other than air), e.g., oxygen or
nitrogen, or steam.
[0057] Other methods of making the fibrous materials include, e.g.,
stone grinding, mechanical ripping or tearing, pin grinding or air
attrition milling.
[0058] If desired, the fibrous materials can be separated, e.g.,
continuously or in batches, into fractions according to their
length, width, density, material type, or some combination of these
attributes. For example, for forming composites, it is often
desirable to have a relatively narrow distribution of fiber
lengths.
[0059] For example, ferrous materials can be separated from any of
the fibrous materials by passing a fibrous material that includes a
ferrous material past a magnet, e.g., an electromagnet, and then
passing the resulting fibrous material through a series of screens,
each screen having different sized apertures.
[0060] The fibrous materials can also be separated, e.g., by using
a high velocity gas, e.g., air. In such an approach, the fibrous
materials are separated by drawing off different fractions, which
can be characterized photonically, if desired. Such a separation
apparatus is discussed in Lindsey et al, U.S. Pat. No.
6,883,667.
[0061] The fibrous materials can be irradiated immediately
following their preparation, or they can may be dried, e.g., at
approximately 105.degree. C. for 4-18 hours, so that the moisture
content is, e.g., less than about 0.5% before use.
[0062] If desired, lignin can be removed from any of the fibrous
materials that include lignin. Also, to aid in the breakdown of the
materials that include the cellulose, the material can be treated
prior to irradiation with heat, a chemical (e.g., mineral acid,
base or a strong oxidizer such as sodium hypochlorite) and/or an
enzyme.
[0063] In some embodiments, the average opening size of the first
screen is less than 0.79 mm ( 1/32 inch, 0.03125 inch), e.g., less
than 0.51 mm ( 1/50 inch, 0.02000 inch), less than 0.40 mm ( 1/64
inch, 0.015625 inch), less than 0.23 mm (0.009 inch), less than
0.20 mm ( 1/128 inch, 0.0078125 inch), less than 0.18 mm (0.007
inch), less than 0.13 mm (0.005 inch), or even less than less than
0.10 mm ( 1/256 inch, 0.00390625 inch). The screen is prepared by
interweaving monofilaments having an appropriate diameter to give
the desired opening size. For example, the monofilaments can be
made of a metal, e.g., stainless steel. As the opening sizes get
smaller, structural demands on the monofilaments may become
greater. For example, for opening sizes less than 0.40 mm, it can
be advantageous to make the screens from monofilaments made from a
material other than stainless steel, e.g., titanium, titanium
alloys, amorphous metals, nickel, tungsten, rhodium, rhenium,
ceramics, or glass. In some embodiments, the screen is made from a
plate, e.g. a metal plate, having apertures, e.g., cut into the
plate using a laser. In some embodiments, the open area of the mesh
is less than 52%, e.g., less than 41%, less than 36%, less than
31%, less than 30%.
[0064] In some embodiments, the second fibrous is sheared and
passed through the first screen, or a different sized screen. In
some embodiments, the second fibrous material is passed through a
second screen having an average opening size equal to or less than
that of the first screen.
[0065] Referring to FIG. 3, a third fibrous material 220 can be
prepared from the second fibrous material 216 by shearing the
second fibrous material 216 and passing the resulting material
through a second screen 222 having an average opening size less
than the first screen 214.
[0066] Generally, the fibers of the fibrous materials can have a
relatively large average length-to-diameter ratio (e.g., greater
than 20-to-1), even if they have been sheared more than once. In
addition, the fibers of the fibrous materials described herein may
have a relatively narrow length and/or length-to-diameter ratio
distribution.
[0067] As used herein, average fiber widths (diameters) are those
determined optically by randomly selecting approximately 5,000
fibers. Average fiber lengths are corrected length-weighted
lengths. BET (Brunauer, Emmet and Teller) surface areas are
multi-point surface areas, and porosities are those determined by
mercury porosimetry.
[0068] The average length-to-diameter ratio of the second fibrous
material 14 can be, e.g., greater than 8/1, e.g., greater than
10/1, greater than 15/1, greater than 20/1, greater than 25/1, or
greater than 50/1. An average length of the second fibrous material
14 can be, e.g., between about 0.5 mm and 2.5 mm, e.g., between
about 0.75 mm and 1.0 mm, and an average width (i.e., diameter) of
the second fibrous material 14 can be, e.g., between about 5 .mu.m
and 50 .mu.m, e.g., between about 10 .mu.m and 30 .mu.m.
[0069] In some embodiments, a standard deviation of the length of
the second fibrous material 14 is less than 60 percent of an
average length of the second fibrous material 14, e.g., less than
50 percent of the average length, less than 40 percent of the
average length, less than 25 percent of the average length, less
than 10 percent of the average length, less than 5 percent of the
average length, or even less than 1 percent of the average
length.
[0070] In some embodiments, a BET surface area of the second
fibrous material is greater than 0.1 m.sup.2/g, e.g., greater than
0.25 m.sup.2/g, greater than 0.5 m.sup.2/g, greater than 1.0
m.sup.2/g, greater than 1.5 m.sup.2/g, greater than 1.75 m.sup.2/g,
greater than 5.0 m.sup.2/g, greater than 10 m.sup.2/g, greater than
25 m.sup.2/g, greater than 35 m.sup.2/g, greater than 50 m.sup.2/g,
greater than 60 m.sup.2/g, greater than 75 m.sup.2/g, greater than
100 m.sup.2/g, greater than 150 m.sup.2/g, greater than 200
m.sup.2/g, or even greater than 250 m.sup.2/g. A porosity of the
second fibrous material 14 can be, e.g., greater than 20 percent,
greater than 25 percent, greater than 35 percent, greater than 50
percent, greater than 60 percent, greater than 70 percent, e.g.,
greater than 80 percent, greater than 85 percent, greater than 90
percent, greater than 92 percent, greater than 94 percent, greater
than 95 percent, greater than 97.5 percent, greater than 99
percent, or even greater than 99.5 percent.
[0071] In some embodiments, a ratio of the average
length-to-diameter ratio of the first fibrous material to the
average length-to-diameter ratio of the second fibrous material is,
e.g., less than 1.5, e.g., less than 1.4, less than 1.25, less than
1.1, less than 1.075, less than 1.05, less than 1.025, or even
substantially equal to 1.
[0072] In particular embodiments, the second fibrous material is
sheared again and the resulting fibrous material passed through a
second screen having an average opening size less than the first
screen to provide a third fibrous material. In such instances, a
ratio of the average length-to-diameter ratio of the second fibrous
material to the average length-to-diameter ratio of the third
fibrous material can be, e.g., less than 1.5, e.g., less than 1.4,
less than 1.25, or even less than 1.1.
[0073] In some embodiments, the third fibrous material is passed
through a third screen to produce a fourth fibrous material. The
fourth fibrous material can be, e.g., passed through a fourth
screen to produce a fifth material. Similar screening processes can
be repeated as many times as desired to produce the desired fibrous
material having the desired properties.
Radiation Treatment
[0074] One or more irradiation processing sequences can be used to
process raw feedstock from a wide variety of different sources to
extract useful substances from the feedstock, and to provide
partially degraded organic material which functions as input to
further processing steps and/or sequences. Irradiation can reduce
the molecular weight and/or crystallinity of feedstock. In some
embodiments, energy deposited in a material that releases an
electron from its atomic orbital is used to irradiate the
materials. The radiation may be provided by 1) heavy charged
particles, such as alpha particles or protons, 2) electrons,
produced, for example, in beta decay or electron beam accelerators,
or 3) electromagnetic radiation, for example, gamma rays, x rays,
or ultraviolet rays. In one approach, radiation produced by
radioactive substances can be used to irradiate the feedstock. In
some embodiments, any combination in any order or concurrently of
(1) through (3) may be utilized. In another approach,
electromagnetic radiation (e.g., produced using electron beam
emitters) can be used to irradiate the feedstock. The doses applied
depend on the desired effect and the particular feedstock. For
example, high doses of radiation can break chemical bonds within
feedstock components and low doses of radiation can increase
chemical bonding (e.g., cross-linking) within feedstock components.
In some instances when chain scission is desirable and/or polymer
chain functionalization is desirable, particles heavier than
electrons, such as protons, helium nuclei, argon ions, silicon
ions, neon ions, carbon ions, phoshorus ions, oxygen ions or
nitrogen ions can be utilized. When ring-opening chain scission is
desired, positively charged particles can be utilized for their
Lewis acid properties for enhanced ring-opening chain scission. For
example, when oxygen-containing functional groups are desired,
irradiation in the presence of oxygen or even irradiation with
oxygen ions can be performed. For example, when nitrogen-containing
functional groups are desirable, irradiation in the presence of
nitrogen or even irradiation with nitrogen ions can be
performed.
[0075] Referring to FIG. 4, in one method, a first material 2 that
is or includes cellulose having a first number average molecular
weight (.sup.TM.sub.N1) is irradiated in an oxidizing environment,
e.g., by treatment in air with ionizing radiation (e.g., in the
form of gamma radiation, X-ray radiation, 100 nm to 280 nm
ultraviolet (UV) light, a beam of electrons or other charged
particles) to provide a second material 3 that includes cellulose
having a second number average molecular weight (.sup.TM.sub.N2)
lower than the first number average molecular weight. The second
material (or the first and second material) can be combined with a
microorganism (e.g., a bacterium or a yeast) that can utilize the
second and/or first material to produce a fuel 5 that is or
includes hydrogen, an alcohol (e.g., ethanol or butanol, such as
n-, sec- or t-butanol), an organic acid, a hydrocarbon or mixtures
of any of these.
[0076] Since the second material 3 has cellulose having a reduced
molecular weight relative to the first material, and in some
instances, a reduced crystallinity as well, the second material is
generally more dispersible, swellable and/or soluble in a solution
containing a microorganism. These properties make the second
material 3 more susceptible to chemical, enzymatic and/or
biological attack relative to the first material 2, which can
greatly improve the production rate and/or production level of a
desired product, e.g., ethanol. Radiation can also sterilize the
materials.
[0077] In some embodiments, the second number average molecular
weight (M.sub.N2) is lower than the first number average molecular
weight (.sup.TM.sub.N1) by more than about 10 percent, e.g., 15,
20, 25, 30, 35, 40, 50 percent, 60 percent, or even more than about
75 percent.
[0078] In some instances, the second material has cellulose that
has as crystallinity (.sup.TC.sub.2) that is lower than the
crystallinity (.sup.TC.sub.1) of the cellulose of the first
material. For example, (.sup.TC.sub.2) can be lower than
(.sup.TC.sub.1) by more than about 10 percent, e.g., 15, 20, 25,
30, 35, 40, or even more than about 50 percent.
[0079] In some embodiments, the starting crystallinity index (prior
to irradiation) is from about 40 to about 87.5 percent, e.g., from
about 50 to about 75 percent or from about 60 to about 70 percent,
and the crystallinity index after irradiation is from about 10 to
about 50 percent, e.g., from about 15 to about 45 percent or from
about 20 to about 40 percent. However, in some embodiments, e.g.,
after extensive irradiation, it is possible to have a crystallinity
index of lower than 5 percent. In some embodiments, the material
after irradiation is substantially amorphous.
[0080] In some embodiments, the starting number average molecular
weight (prior to irradiation) is from about 200,000 to about
3,200,000, e.g., from about 250,000 to about 1,000,000 or from
about 250,000 to about 700,000, and the number average molecular
weight after irradiation is from about 50,000 to about 200,000,
e.g., from about 60,000 to about 150,000 or from about 70,000 to
about 125,000. However, in some embodiments, e.g., after extensive
irradiation, it is possible to have a number average molecular
weight of less than about 10,000 or even less than about 5,000.
[0081] In some embodiments, the second material can have a level of
oxidation (.sup.TO.sub.2) that is higher than the level of
oxidation (.sup.TO.sub.1) of the first material. A higher level of
oxidation of the material can aid in its dispersibility,
swellability and/or solubility, further enhancing the materials
susceptibility to chemical, enzymatic or biological attack.
Ionizing Radiation
[0082] Each form of radiation ionizes the biomass via particular
interactions, as determined by the energy of the radiation. Heavy
charged particles primarily ionize matter via Coulomb scattering;
furthermore, these interactions produce energetic electrons that
may further ionize matter. Alpha particles are identical to the
nucleus of a helium atom and are produced by the alpha decay of
various radioactive nuclei, such as isotopes of bismuth, polonium,
astatine, radon, francium, radium, several actinides, such as
actinium, thorium, uranium, neptunium, curium, californium,
americium, and plutonium.
[0083] When particles are utilized, they can be neutral
(uncharged), positively charged or negatively charged. When
charged, the charged particles can bear a single positive or
negative charge, or multiple charges, e.g., one, two, three or even
four or more charges. In instances in which chain scission is
desired, positively charged particles may be desirable, in part,
due to their acidic nature. When particles are utilized, the
particles can have the mass of a resting electron, or greater,
e.g., 500, 1000, 1500, or 2000 or more times the mass of a resting
electron. For example, the particles can have a mass of from about
1 atomic unit to about 150 atomic units, e.g., from about 1 atomic
unit to about 50 atomic units, or from about 1 to about 25, e.g.,
1, 2, 3, 4, 5, 10, 12 or 15 amu. Accelerators used to accelerate
the particles can be electrostatic DC, electrodynamic DC, RF
linear, magnetic induction linear or continuous wave. For example,
cyclotron type accelerators are available from IBA, Belgium, such
as the Rhodotron.RTM. system, while DC type accelerators are
available from RDI, now IBA Industrial, such as the
Dynamitron.RTM.. Ions and ion accelerators are discussed in
Introductory Nuclear Physics, Kenneth S. Krane, John Wiley &
Sons, Inc. (1988), Krsto Prelec, FIZIKA B 6 (1997) 4, 177-206, Chu,
William T., "Overview of Light-Ion Beam Therapy", Columbus-Ohio,
ICRU-IAEA Meeting, 18-20 Mar. 2006, Iwata, Y. et al.,
"Alternating-Phase-Focused IH-DTL for Heavy-Ion Medical
Accelerators", Proceedings of EPAC 2006, Edinburgh, Scotland, and
Leitner, C. M. et al., "Status of the Superconducting ECR Ion
Source Venus", Proceedings of EPAC 2000, Vienna. Typically,
generators are housed in a vault, e.g., of lead or concrete.
[0084] Electrons interact via Coulomb scattering and
bremssthrahlung radiation produced by changes in the velocity of
electrons. Electrons may be produced by radioactive nuclei that
undergo beta decay, such as isotopes of iodine, cesium, technetium,
and iridium. Alternatively, an electron gun can be used as an
electron source via thermionic emission.
[0085] Electromagnetic radiation interacts via three processes:
photoelectric absorption, Compton scattering, and pair production.
The dominating interaction is determined by the energy of the
incident radiation and the atomic number of the material. The
summation of interactions contributing to the absorbed radiation in
cellulosic material can be expressed by the mass absorption
coefficient (see "Ionization Radiation" in PCT/US2007/022719).
[0086] Electromagnetic radiation is subclassified as gamma rays, x
rays, ultraviolet rays, infrared rays, microwaves, or radiowaves,
depending on its wavelength.
[0087] For example, gamma radiation can be employed to irradiate
the materials. Referring to FIGS. 5 and 6 (an enlarged view of
region R), a gamma irradiator 10 includes gamma radiation sources
408, e.g., .sup.60Co pellets, a working table 14 for holding the
materials to be irradiated and storage 16, e.g., made of a
plurality iron plates, all of which are housed in a concrete
containment chamber (vault) 20 that includes a maze entranceway 22
beyond a lead-lined door 26. Storage 16 includes a plurality of
channels 30, e.g., sixteen or more channels, allowing the gamma
radiation sources to pass through storage on their way proximate
the working table.
[0088] In operation, the sample to be irradiated is placed on a
working table. The irradiator is configured to deliver the desired
dose rate and monitoring equipment is connected to an experimental
block 31. The operator then leaves the containment chamber, passing
through the maze entranceway and through the lead-lined door. The
operator mans a control panel 32, instructing a computer 33 to lift
the radiation sources 12 into working position using cylinder 36
attached to a hydraulic pump 40.
[0089] Gamma radiation has the advantage of a significant
penetration depth into a variety of materials in the sample.
Sources of gamma rays include radioactive nuclei, such as isotopes
of cobalt, calcium, technicium, chromium, gallium, indium, iodine,
iron, krypton, samarium, selenium, sodium, thalium, and xenon.
[0090] Sources of x rays include electron beam collision with metal
targets, such as tungsten or molybdenum or alloys, or compact light
sources, such as those produced commercially by Lyncean.
[0091] Sources for ultraviolet radiation include deuterium or
cadmium lamps.
[0092] Sources for infrared radiation include sapphire, zinc, or
selenide window ceramic lamps.
[0093] Sources for microwaves include klystrons, Slevin type RF
sources, or atom beam sources that employ hydrogen, oxygen, or
nitrogen gases.
Electron Beam
[0094] In some embodiments, a beam of electrons is used as the
radiation source. A beam of electrons has the advantages of high
dose rates (e.g., 1, 5, or even 10 Mrad per second), high
throughput, less containment, and less confinement equipment.
Electrons can also be more efficient at causing chain scission. In
addition, electrons having energies of 4-10 MeV can have a
penetration depth of 5 to 30 mm or more, such as 40 mm. In low bulk
density materials, e.g., materials having a bulk density of less
than about 0.35 grams per cubic centimeter, penetration depths can
be even higher. For example, with a 5 MeV electron gun, penetration
through a low bulk density material can be 5 to 6 inches or
more.
[0095] Electron beams can be generated, e.g., by electrostatic
generators, cascade generators, transformer generators, low energy
accelerators with a scanning system, low energy accelerators with a
linear cathode, linear accelerators, and pulsed accelerators.
Electrons as an ionizing radiation source can be useful, e.g., for
relatively thin piles of materials, e.g., less than 0.5 inch, e.g.,
less than 0.4 inch, 0.3 inch, 0.2 inch, or less than 0.1 inch. In
some embodiments, the energy of each electron of the electron beam
is from about 0.3 MeV to about 2.0 MeV (million electron volts),
e.g., from about 0.5 MeV to about 1.5 MeV, or from about 0.7 MeV to
about 1.25 MeV. In other embodiments, the energy of each electron
is at least about 3 MeV, e.g., at least about 4, 5 or 6 MeV.
[0096] Electron beam irradiation devices may be procured
commercially from Ion Beam Applications, Louvain-la-Neuve, Belgium
or the Titan Corporation, San Diego, Calif. Typical electron
energies can be 1 MeV, 2 MeV, 4.5 MeV, 7.5 MeV, or 10 MeV. Typical
electron beam irradiation device power can be 1 kW, 5 kW, 10 kW, 20
kW, 50 kW, 100 kW, 250 kW, or 500 kW. Typical doses may take values
of 1 kGy, 5 kGy, 10 kGy, 20 kGy, 50 kGy, 100 kGy, or 200 kGy.
Irradiating Devices
[0097] Various irradiating devices may be used in the methods
disclosed herein, including field ionization sources, electrostatic
ion separators, field ionization generators, thermionic emission
sources, microwave discharge ion sources, recirculating or static
accelerators, dynamic linear accelerators, van de Graaff
accelerators, and folded tandem accelerators. Such devices are
disclosed, for example, in U.S. Provisional Application Ser. No.
61/073,665, the complete disclosure of which is incorporated herein
by reference.
Electromagnetic Radiation
[0098] In embodiments in which the irradiating is performed with
electromagnetic radiation, the electromagnetic radiation can have,
e.g., energy per photon (in electron volts) of greater than
10.sup.2 eV, e.g., greater than 10.sup.3, 10.sup.4, 10.sup.5,
10.sup.6, or even greater than 10.sup.7 eV. In some embodiments,
the electromagnetic radiation has energy per photon of between
10.sup.4 and 10.sup.7, e.g., between 10.sup.5 and 10.sup.6 eV. The
electromagnetic radiation can have a frequency of, e.g., greater
than 10.sup.16 Hz, greater than 10.sup.17 Hz, 10.sup.18, 10.sup.19,
10.sup.20, or even greater than 10.sup.21 Hz. In some embodiments,
the electromagnetic radiation has a frequency of between 10.sup.18
and 10.sup.22 Hz, e.g., between 10.sup.19 to 10.sup.21 Hz.
Doses
[0099] In some embodiments, the irradiating (with any radiation
source or a combination of sources) is performed until the material
receives a dose of at least 0.25 Mrad, e.g., at least 1.0 Mrad, at
least 2.5 Mrad, at least 5.0 Mrad, at least 10.0 Mrad, at least
about 25, at least about 50, at least about 70, or at least about
80 MRad. In some embodiments, the irradiating is performed until
the material receives a dose of between 1.0 Mrad and 50 Mrad, e.g.,
between 1.5 Mrad and 40 Mrad.
[0100] In some embodiments, the irradiating is performed at a dose
rate of between 5.0 and 1500.0 kilorads/hour, e.g., between 10.0
and 750.0 kilorads/hour or between 50.0 and 350.0
kilorads/hours.
[0101] In some embodiments, two or more radiation sources are used,
such as two or more ionizing radiations. For example, samples can
be treated, in any order, with a beam of electrons, followed by
gamma radiation and UV light having wavelengths from about 100 nm
to about 280 nm. In some embodiments, samples are treated with
three ionizing radiation sources, such as a beam of electrons,
gamma radiation, and energetic UV light.
Quenching and Controlled Functionalization of Biomass
[0102] After treatment with one or more ionizing radiations, such
as photonic radiation (e.g., X-rays or gamma-rays), e-beam
radiation or particles heavier than electrons that are positively
or negatively charged (e.g., protons or carbon ions), any of the
carbohydrate-containing materials or mixtures described herein
become ionized; that is, they include radicals at levels that are
detectable with an electron spin resonance spectrometer. The
current practical limit of detection of the radicals is about
10.sup.14 spins at room temperature. After ionization, any biomass
material that has been ionized can be quenched to reduce the level
of radicals in the ionized biomass, e.g., such that the radicals
are no longer detectable with the electron spin resonance
spectrometer. For example, the radicals can be quenched by the
application of a sufficient pressure to the biomass and/or
utilizing a fluid in contact with the ionized biomass, such as a
gas or liquid, that reacts with (quenches) the radicals. The use of
a gas or liquid to at least aid in the quenching of the radicals
also allows the operator to control functionalization of the
ionized biomass with a desired amount and kinds of functional
groups, such as carboxylic acid groups, enol groups, aldehyde
groups, nitro groups, nitrile groups, amino groups, alkyl amino
groups, alkyl groups, chloroalkyl groups or chlorofluoroalkyl
groups. In some instances, such quenching can improve the stability
of some of the ionized biomass materials. For example, quenching
can improve the resistance of the biomass to oxidation.
Functionalization can also improve the solubility of any biomass
described herein, can improve its thermal stability, and can
improve material utilization by various microorganisms. For
example, the functional groups imparted to the biomass material by
quenching can act as receptor sites for attachment by
microorganisms, e.g., to enhance cellulose hydrolysis by various
microorganisms.
[0103] FIG. 7 illustrates changing a molecular and/or a
supramolecular structure of a biomass feedstock by pretreating the
biomass feedstock with ionizing radiation, such as with electrons
or ions of sufficient energy to ionize the biomass feedstock, to
provide a first level of radicals. As shown in FIG. 7, if the
ionized biomass remains in the atmosphere, it will be oxidized,
such as to an extent that carboxylic acid groups are generated by
reacting with the atmospheric oxygen in air. In some instances with
some materials, such oxidation is desired because it can aid in the
further breakdown in molecular weight of the
carbohydrate-containing biomass, and the oxidation groups, e.g.,
carboxylic acid groups can be helpful for solubility and
microorganism utilization in some instances. However, since the
radicals can "live" for some time after irradiation, e.g., longer
than 1 day, 5 days, 30 days, 3 months, 6 months or even longer than
1 year, material properties can continue to change over time, which
in some instances can be undesirable. Detecting radicals in
irradiated samples by electron spin resonance spectroscopy and
radical lifetimes in such samples is discussed in Bartolotta et
al., Physics in Medicine and Biology, 46 (2001), 461-471 and in
Bartolotta et al., Radiation Protection Dosimetry, Vol. 84, Nos.
1-4, pp. 293-296 (1999). As shown in FIG. 7, the ionized biomass
can be quenched to functionalize and/or to stabilize the ionized
biomass. At any point, e.g., when the material is "alive",
"partially alive" or fully quenched, the pretreated biomass can be
converted into a product.
[0104] In some embodiments, the quenching includes an application
of pressure to the biomass, such as by mechanically deforming the
biomass, e.g., directly mechanically compressing the biomass in
one, two, or three dimensions, or applying pressure to a fluid in
which the biomass is immersed, e.g., isostatic pressing. In such
instances, the deformation of the material itself brings radicals,
which are often trapped in crystalline domains, in sufficient
proximity so that the radicals can recombine, or react with another
group. In some instances, the pressure is applied together with the
application of heat, such as a sufficient quantity of heat to
elevate the temperature of the biomass to above a melting point or
softening point of a component of the biomass, such as lignin,
cellulose or hemicellulose. Heat can improve molecular mobility in
the polymeric material, which can aid in the quenching of the
radicals. When pressure is utilized to quench, the pressure can be
greater than about 1000 psi, such as greater than about 1250 psi,
1450 psi, 3625 psi, 5075 psi, 7250 psi, 10000 psi or even greater
than 15000 psi.
[0105] In some embodiments, quenching includes contacting the
biomass with a fluid, such as a liquid or gas, e.g., a gas capable
of reacting with the radicals, such as acetylene or a mixture of
acetylene in nitrogen, ethylene, chlorinated ethylenes or
chlorofluoroethylenes, propylene or mixtures of these gases. In
other particular embodiments, quenching includes contacting the
biomass with a liquid, e.g., a liquid soluble in, or at least
capable of penetrating into the biomass and reacting with the
radicals, such as a diene, such as 1,5-cyclooctadiene. In some
specific embodiments, the quenching includes contacting the biomass
with an antioxidant, such as Vitamin E. If desired, the biomass
feedstock can include an antioxidant dispersed therein, and the
quenching can come from contacting the antioxidant dispersed in the
biomass feedstock with the radicals.
[0106] Other methods for quenching are possible. For example, any
method for quenching radicals in polymeric materials described in
Muratoglu et al., U.S. Patent Application Publication No.
2008/0067724 and Muratoglu et al., U.S. Pat. No. 7,166,650 can be
utilized for quenching any ionized biomass material described
herein. Furthermore any quenching agent (described as a
"sensitizing agent" in the above-noted Muratoglu disclosures)
and/or any antioxidant described in either Muratoglu reference can
be utilized to quench any ionized biomass material.
[0107] Functionalization can be enhanced by utilizing heavy charged
ions, such as any of the heavier ions described herein. For
example, if it is desired to enhance oxidation, charged oxygen ions
can be utilized for the irradiation. If nitrogen functional groups
are desired, nitrogen ions or ions that includes nitrogen can be
utilized. Likewise, if sulfur or phosphorus groups are desired,
sulfur or phosphorus ions can be used in the irradiation.
[0108] In some embodiments, from about 1 out of every 2 to about 1
out of every 250 saccharide units includes a carboxylic acid group,
or an ester or salt thereof; whereas the native or unprocessed base
material can have less than 1 carboxylic acid group per 300
saccharide units. In other embodiments, from about 1 out of every 5
to about 1 out of every 250 saccharide units, e.g., 1 out of every
8 to about 1 out of every 100 units or from 1 out of 10 to about 1
out of 50 units includes a carboxylic acid group, or an ester or
salt thereof.
[0109] In some embodiments, from about 1 out of every 5 to about 1
out of every 1500 saccharide units includes a nitrile group, a
nitroso groups or a nitro group. In other embodiments, from about 1
out of every 10 to about 1 out of every 1000 saccharide units,
e.g., 1 out of every 25 to about 1 out of every 1000 units or from
1 out of 35 to about 1 out of 750 units includes a nitrile group, a
nitroso groups or a nitro group.
[0110] In some embodiments, the saccharide units include mixtures
of carboxylic acid groups, nitrile groups, nitroso groups and nitro
groups. Mixed groups can enhance the solubility of a cellulosic or
lignocellulosic material.
Particle Beam Exposure in Fluids
[0111] In some cases, the cellulosic or lignocellulosic materials
can be exposed to a particle beam in the presence of one or more
additional fluids (e.g., gases and/or liquids). Exposure of a
material to a particle beam in the presence of one or more
additional fluids can increase the efficiency of the treatment.
[0112] In some embodiments, the material is exposed to a particle
beam in the presence of a fluid such as air. Particles accelerated
in any one or more of the types of accelerators disclosed herein
(or another type of accelerator) are coupled out of the accelerator
via an output port (e.g., a thin membrane such as a metal foil),
pass through a volume of space occupied by the fluid, and are then
incident on the material. In addition to directly treating the
material, some of the particles generate additional chemical
species by interacting with fluid particles (e.g., ions and/or
radicals generated from various constituents of air, such as ozone
and oxides of nitrogen). These generated chemical species can also
interact with the material, and can act as initiators for a variety
of different chemical bond-breaking reactions in the material. For
example, any oxidant produced can oxidize the material, which can
result in molecular weight reduction.
[0113] In certain embodiments, additional fluids can be selectively
introduced into the path of a particle beam before the beam is
incident on the material. As discussed above, reactions between the
particles of the beam and the particles of the introduced fluids
can generate additional chemical species, which react with the
material and can assist in functionalizing the material, and/or
otherwise selectively altering certain properties of the material.
The one or more additional fluids can be directed into the path of
the beam from a supply tube, for example. The direction and flow
rate of the fluid(s) that is/are introduced can be selected
according to a desired exposure rate and/or direction to control
the efficiency of the overall treatment, including effects that
result from both particle-based treatment and effects that are due
to the interaction of dynamically generated species from the
introduced fluid with the material. In addition to air, exemplary
fluids that can be introduced into the ion beam include oxygen,
nitrogen, one or more noble gases, one or more halogens, and
hydrogen.
Process Water
[0114] In the processes disclosed herein, whenever water is used in
any process, it may be grey water, e.g., municipal grey water, or
black water. In some embodiments, the grey or black water is
sterilized prior to use. Sterilization may be accomplished by any
desired technique, for example by irradiation, steam, or chemical
sterilization.
Examples
[0115] The following Examples are intended to illustrate, and do
not limit the teachings of this disclosure.
Example 1
Preparation of Fibrous Material from Polycoated Paper
[0116] A 1500 pound skid of virgin, half-gallon juice cartons made
of un-printed polycoated white Kraft board having a bulk density of
20 lb/ft.sup.3 was obtained from International Paper. Each carton
was folded flat, and then fed into a 3 hp Flinch Baugh shredder at
a rate of approximately 15 to 20 pounds per hour. The shredder was
equipped with two 12 inch rotary blades, two fixed blades and a
0.30 inch discharge screen. The gap between the rotary and fixed
blades was adjusted to 0.10 inch. The output from the shredder
resembled confetti having a width of between 0.1 inch and 0.5 inch,
a length of between 0.25 inch and 1 inch and a thickness equivalent
to that of the starting material (about 0.075 inch).
[0117] The confetti-like material was fed to a Munson rotary knife
cutter, Model SC30. Model SC30 is equipped with four rotary blades,
four fixed blades, and a discharge screen having 1/8 inch openings.
The gap between the rotary and fixed blades was set to
approximately 0.020 inch. The rotary knife cutter sheared the
confetti-like pieces across the knife-edges, tearing the pieces
apart and releasing a fibrous material at a rate of about one pound
per hour. The fibrous material had a BET surface area of 0.9748
m.sup.2/g.+-.0.0167 m.sup.2/g, a porosity of 89.0437 percent and a
bulk density (@0.53 psia) of 0.1260 g/mL. An average length of the
fibers was 1.141 mm and an average width of the fibers was 0.027
mm, giving an average L/D of 42:1. A scanning electron micrograph
of the fibrous material is shown in FIG. 8 at 25.times.
magnification.
Example 2
Preparation of Fibrous Material from Bleached Kraft Board
[0118] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti having a
width of between 0.1 inch and 0.5 inch, a length of between 0.25
inch and 1 inch and a thickness equivalent to that of the starting
material (about 0.075 inch). The confetti-like material was fed to
a Munson rotary knife cutter, Model SC30. The discharge screen had
1/8 inch openings. The gap between the rotary and fixed blades was
set to approximately 0.020 inch. The rotary knife cutter sheared
the confetti-like pieces, releasing a fibrous material at a rate of
about one pound per hour. The fibrous material had a BET surface
area of 1.1316 m.sup.2/g.+-.0.0103 m.sup.2/g, a porosity of 88.3285
percent and a bulk density (@0.53 psia) of 0.1497 g/mL. An average
length of the fibers was 1.063 mm and an average width of the
fibers was 0.0245 mm, giving an average L/D of 43:1. A scanning
electron micrographs of the fibrous material is shown in FIG. 9 at
25.times. magnification.
Example 3
Preparation of Twice Sheared Fibrous Material from Bleached Kraft
Board
[0119] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti (as above).
The confetti-like material was fed to a Munson rotary knife cutter,
Model SC30. The discharge screen had 1/16 inch openings. The gap
between the rotary and fixed blades was set to approximately 0.020
inch. The rotary knife cutter the confetti-like pieces, releasing a
fibrous material at a rate of about one pound per hour. The
material resulting from the first shearing was fed back into the
same setup described above and sheared again. The resulting fibrous
material had a BET surface area of 1.4408 m.sup.2/g.+-.0.0156
m.sup.2/g, a porosity of 90.8998 percent and a bulk density (@0.53
psia) of 0.1298 g/mL. An average length of the fibers was 0.891 mm
and an average width of the fibers was 0.026 mm, giving an average
L/D of 34:1. A scanning electron micrograph of the fibrous material
is shown in FIG. 10 at 25.times. magnification.
Example 4
Preparation of Thrice Sheared Fibrous Material from Bleached Kraft
Board
[0120] A 1500 pound skid of virgin bleached white Kraft board
having a bulk density of 30 lb/ft.sup.3 was obtained from
International Paper. The material was folded flat, and then fed
into a 3 hp Flinch Baugh shredder at a rate of approximately 15 to
20 pounds per hour. The shredder was equipped with two 12 inch
rotary blades, two fixed blades and a 0.30 inch discharge screen.
The gap between the rotary and fixed blades was adjusted to 0.10
inch. The output from the shredder resembled confetti (as above).
The confetti-like material was fed to a Munson rotary knife cutter,
Model SC30. The discharge screen had 1/8 inch openings. The gap
between the rotary and fixed blades was set to approximately 0.020
inch. The rotary knife cutter sheared the confetti-like pieces
across the knife-edges. The material resulting from the first
shearing was fed back into the same setup and the screen was
replaced with a 1/16 inch screen. This material was sheared. The
material resulting from the second shearing was fed back into the
same setup and the screen was replaced with a 1/32 inch screen.
This material was sheared. The resulting fibrous material had a BET
surface area of 1.6897 m.sup.2/g.+-.0.0155 m.sup.2/g, a porosity of
87.7163 percent and a bulk density (@0.53 psia) of 0.1448 g/mL. An
average length of the fibers was 0.824 mm and an average width of
the fibers was 0.0262 mm, giving an average L/D of 32:1. A scanning
electron micrograph of the fibrous material is shown in FIG. 11 at
25.times. magnification.
Example 5
Gamma and Electron Beam Processing
[0121] Sample materials presented in the following tables include
Kraft paper (P), wheat straw (WS), alfalfa (A), and switchgrass
(SG). Samples were treated with electron beam using a vaulted
Rhodotron.RTM. TT200 continuous wave accelerator delivering 5 MeV
electrons at 80 kW of output power. Table 1 describes the
parameters used. Table 2 reports the nominal dose used for the
Sample ID (in MRad) and the corresponding dose delivered to the
sample (in kgy).
TABLE-US-00001 TABLE 1 Rhodotron .RTM. TT 200 Parameters Beam Beam
Produced: Accelerated electrons Beam energy: Nominal (fixed): 5 MeV
(+0 keV-250 keV Energy dispersion at 10 Mev: Full width half
maximum (FWHM) 300 keV Beam power at 10 MeV: Guaranteed Operating
Range 1 to 80 kW Power Consumption Stand-by condition (vacuum and
cooling ON): <15 kW At 50 kW beam power: <210 kW At 80 kW
beam power: <260 kW RF System Frequency: 107.5 .+-. 1 MHz
Tetrode type: Thomson TH781 Scanning Horn Nominal Scanning Length
(measured at 25-35 120 cm cm from window): Scanning Range: From 30%
to 100% of Nominal Scanning Length Nominal Scanning Frequency (at
max. 100 Hz .+-. 5% scanning length): Scanning Uniformity (across
90% of Nominal .+-.5% Scanning Length)
TABLE-US-00002 TABLE 2 Dosages Delivered to Sample Using E-Beam
Total Dosage (MRad) (Number Associated with Sample ID Delivered
Dose (kgy).sup.1 1 9.9 3 29.0 5 50.4 7 69.2 10 100.0 15 150.3 20
198.3 30 330.9 50 529.0 70 695.9 100 993.6 .sup.1For example, 9.9
kgy was delivered in 11 seconds at a beam current of 5 mA and a
line speed of 12.9 feet/minute. Cool time between treatments was
around 2 minutes.
[0122] The number "132" of the Sample ID refers to the particle
size of the material after shearing through a 1/32 inch screen. The
number after the dash refers to the dosage of radiation (MRad). For
example, a sample ID "P132-10" refers to Kraft paper that has been
sheared to a particle size of 132 mesh and has been gamma
irradiated with 10 MRad.
[0123] For samples that were irradiated with e-beam, the number
following the dash refers to the amount of energy delivered to the
sample. For example, a sample ID "P-100e" refers to Kraft paper
that has been delivered a dose of energy of about 100 MRad or about
1000 kgy (Table 2).
TABLE-US-00003 TABLE 3 Peak Average Molecular Weight of Gamma
Irradiated Kraft Paper Dosage.sup.1 Average Sample Source Sample ID
(MRad) MW .+-. Std Dev. Kraft Paper P132 0 32853 .+-. 10006 P132-10
10 61398 .+-. 2468** P132-100 100 8444 .+-. 580 **Low doses of
radiation appear to increase the molecular weight of some materials
.sup.1Dosage Rate = 1 MRad/hour
TABLE-US-00004 TABLE 4 Peak Average Molecular Weight of Irradiated
Kraft Paper with E-Beam Dosage Average Sample Source Sample ID
(MRad) MW .+-. Std Dev. Kraft Paper P-1e 1 63489 .+-. 595 P-5e 5
56587 .+-. 536 P-10e 10 53610 .+-. 327 P-30e 30 38231 .+-. 124
P-70e 70 12011 .+-. 158 P-100e 100 9770 .+-. 2
TABLE-US-00005 TABLE 5 Peak Average Molecular Weight of Gamma
Irradiated Materials Dosage.sup.1 Average Sample ID Peak # (MRad)
MW .+-. Std Dev. WS132 1 0 1407411 .+-. 175191 2 '' 39145 .+-. 3425
3 '' 2886 .+-. 177 WS132-10* 1 10 26040 .+-. 3240 WS132-100* 1 100
23620 .+-. 453 A132 1 0 1604886 .+-. 151701 2 '' 37525 .+-. 3751 3
'' 2853 .+-. 490 A132-10* 1 10 50853 .+-. 1665 2 '' 2461 .+-. 17
A132-100* 1 100 38291 .+-. 2235 2 '' 2487 .+-. 15 SG132 1 0 1557360
.+-. 83693 2 '' 42594 .+-. 4414 3 '' 3268 .+-. 249 SG132-10* 1 10
60888 .+-. 9131 SG132-100* 1 100 22345 .+-. 3797 *Peaks coalesce
after treatment **Low doses of radiation appear to increase the
molecular weight of some materials .sup.1Dosage Rate = 1
MRad/hour
TABLE-US-00006 TABLE 6 Peak Average Molecular Weight of Irradiated
Material with E-Beam Average Sample ID Peak # Dosage MW .+-. STD
DEV. A-1e 1 1 1004783 .+-. 97518 2 34499 .+-. 482 3 2235 .+-. 1
A-5e 1 5 38245 .+-. 346 2 2286 .+-. 35 A-10e 1 10 44326 .+-. 33 2
2333 .+-. 18 A-30e 1 30 47366 .+-. 583 2 2377 .+-. 7 A-50e 1 50
32761 .+-. 168 2 2435 .+-. 6 G-1e 1 1 447362 .+-. 38817 2 32165
.+-. 779 3 3004 .+-. 25 G-5e 1 5 62167 .+-. 6418 2 2444 .+-. 33
G-10e 1 10 72636 .+-. 4075 2 3065 .+-. 34 G-30e 1 30 17159 .+-. 390
G-50e 1 50 18960 .+-. 142
[0124] Gel Permeation Chromatography (GPC) is used to determine the
molecular weight distribution of polymers. During GPC analysis, a
solution of the polymer sample is passed through a column packed
with a porous gel trapping small molecules. The sample is separated
based on molecular size with larger molecules eluting sooner than
smaller molecules. The retention time of each component is most
often detected by refractive index (RI), evaporative light
scattering (ELS), or ultraviolet (UV) and compared to a calibration
curve. The resulting data is then used to calculate the molecular
weight distribution for the sample.
[0125] A distribution of molecular weights rather than a unique
molecular weight is used to characterize synthetic polymers. To
characterize this distribution, statistical averages are utilized.
The most common of these averages are the "number average molecular
weight" (M.sub.n) and the "weight average molecular weight"
(M.sub.w). Methods of calculating these values are described in the
art, e.g., in Example 9 of WO 2008/073186,
[0126] The polydispersity index or PI is defined as the ratio of
M.sub.w/M.sub.n. The larger the PI, the broader or more disperse
the distribution. The lowest value that a PI can be is 1. This
represents a monodisperse sample; that is, a polymer with all of
the molecules in the distribution being the same molecular
weight.
[0127] The peak molecular weight value (M.sub.P) is another
descriptor defined as the mode of the molecular weight
distribution. It signifies the molecular weight that is most
abundant in the distribution. This value also gives insight to the
molecular weight distribution.
[0128] Most GPC measurements are made relative to a different
polymer standard. The accuracy of the results depends on how
closely the characteristics of the polymer being analyzed match
those of the standard used. The expected error in reproducibility
between different series of determinations, calibrated separately,
is around 5-10% and is characteristic to the limited precision of
GPC determinations. Therefore, GPC results are most useful when a
comparison between the molecular weight distributions of different
samples is made during the same series of determinations.
[0129] The lignocellulosic samples required sample preparation
prior to GPC analysis. First, a saturated solution (8.4% by weight)
of lithium chloride (LiCl) was prepared in dimethyl acetamide
(DMAc). Approximately 100 mg of each sample was added to
approximately 10 g of a freshly prepared saturated LiCl/DMAc
solution, and the mixtures were heated to approximately 150.degree.
C.-170.degree. C. with stirring for 1 hour. The resulting solutions
were generally light- to dark-yellow in color. The temperature of
the solutions was decreased to approximately 100.degree. C. and the
solutions were heated for an additional 2 hours. The temperature of
the solutions was then decreased to approximately 50.degree. C. and
the sample solutions were heated for approximately 48 to 60 hours.
Of note, samples irradiated at 100 MRad were more easily
solubilized as compared to their untreated counterpart.
Additionally, the sheared samples (denoted by the number 132) had
slightly lower average molecular weights as compared with uncut
samples.
[0130] The resulting sample solutions were diluted 1:1 using DMAc
as solvent and were filtered through a 0.45 .mu.m PTFE filter. The
filtered sample solutions were then analyzed by GPC using the
parameters described in Table 7. The peak average molecular weights
(Mp) of the samples, as determined by Gel Permeation Chromatography
(GPC), are summarized in Tables 3-6. Each sample was prepared in
duplicate and each preparation of the sample was analyzed in
duplicate (two injections) for a total of four injections per
sample. The EasiCal.RTM. polystyrene standards PS1A and PS1B were
used to generate a calibration curve for the molecular weight scale
from about 580 to 7,500,00 Daltons.
TABLE-US-00007 TABLE 7 GPC Analysis Conditions Instrument: Waters
Alliance GPC 2000 Plgel 10.mu. Mixed-B Columns (3): S/N's:
10M-MB-148-83; 10M-MB- 148-84; 10M-MB-174-129 Mobile Phase
(solvent): 0.5% LiCl in DMAc (1.0 mL/min.) Column/Detector
Temperature: 70.degree. C. Injector Temperature: 70.degree. C.
Sample Loop Size: 323.5 .mu.L
Example 6
Time-Of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) Surface
Analysis
[0131] Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) is
a surface-sensitive spectroscopy that uses a pulsed ion beam (Cs or
microfocused Ga) to remove molecules from the very outermost
surface of the sample. The particles are removed from atomic
monolayers on the surface (secondary ions). These particles are
then accelerated into a "flight tube" and their mass is determined
by measuring the exact time at which they reach the detector (i.e.
time-of-flight). ToF-SIMS provides detailed elemental and molecular
information about the surface, thin layers, interfaces of the
sample, and gives a full three-dimensional analysis. The use is
widespread, including semiconductors, polymers, paint, coatings,
glass, paper, metals, ceramics, biomaterials, pharmaceuticals and
organic tissue. Since ToF-SIMS is a survey technique, all the
elements in the periodic table, including H, are detected. ToF-SIMS
data is presented in Tables 8-11. Parameters used are reported in
Table 12.
TABLE-US-00008 TABLE 8 Normalized Mean Intensities of Various
Positive Ions of Interest (Normalized relative to total ion counts
.times. 10000) P132 P132-10 P132-100 m/z species Mean .sigma. Mean
.sigma. Mean .sigma. 23 Na 257 28 276 54 193 36 27 Al 647 43 821
399 297 44 28 Si 76 45.9 197 89 81.7 10.7 15 CH.sub.3 77.9 7.8 161
26 133 12 27 C.sub.2H.sub.3 448 28 720 65 718 82 39 C.sub.3H.sub.3
333 10 463 37 474 26 41 C.sub.3H.sub.5 703 19 820 127 900 63 43
C.sub.3H.sub.7 657 11 757 162 924 118 115 C.sub.9H.sub.7 73 13.4
40.3 4.5 42.5 15.7 128 C.sub.10H.sub.8 55.5 11.6 26.8 4.8 27.7 6.9
73 C.sub.3H.sub.9Si* 181 77 65.1 18.4 81.7 7.5 147
C.sub.5H.sub.15OSi.sub.2* 72.2 33.1 24.9 10.9 38.5 4 207
C.sub.5H.sub.15O.sub.3Si.sub.3* 17.2 7.8 6.26 3.05 7.49 1.77 647
C.sub.42H.sub.64PO.sub.3 3.63 1.05 1.43 1.41 10.7 7.2
TABLE-US-00009 TABLE 9 Normalized Mean Intensities of Various
Negative Ions of Interest (Normalized relative to total ion counts
.times. 10000) P132 P132-10 P132-100 m/z species Mean .sigma. Mean
.sigma. Mean .sigma. 19 F 15.3 2.1 42.4 37.8 19.2 1.9 35 Cl 63.8
2.8 107 33 74.1 5.5 13 CH 1900 91 1970 26 1500 6 25 C.sub.2H 247
127 220 99 540 7 26 CN 18.1 2.1 48.6 30.8 43.9 1.4 42 CNO 1.16 0.71
0.743 0.711 10.8 0.9 46 NO.sub.2 1.87 0.38 1.66 1.65 12.8 1.8
TABLE-US-00010 TABLE 10 Normalized Mean Intensities of Various
Positive Ions of Interest (Normalized relative to total ion counts
.times. 10000) P-1e P-5e P-10e P-30e P-70e P-100e m/z Species Mean
.sigma. Mean .sigma. Mean .sigma. Mean .sigma. Mean .sigma. Mean
.sigma. 23 Na 232 56 370 37 241 44 518 57 350 27 542 104 27 Al 549
194 677 86 752 371 761 158 516 159 622 166 28 Si 87.3 11.3 134 24
159 100 158 32 93.7 17.1 124 11 15 CH.sub.3 114 23 92.9 3.9 128 18
110 16 147 16 141 5 27 C.sub.2H.sub.3 501 205 551 59 645 165 597
152 707 94 600 55 39 C.sub.3H.sub.3 375 80 288 8 379 82 321 57 435
61 417 32 41 C.sub.3H.sub.5 716 123 610 24 727 182 607 93 799 112
707 84 43 C.sub.3H.sub.7 717 121 628 52 653 172 660 89 861 113 743
73 115 C.sub.9H.sub.7 49.9 14.6 43.8 2.6 42.2 7.9 41.4 10.1 27.7 8
32.4 10.5 128 C.sub.10H.sub.8 38.8 13.1 39.2 1.9 35.2 11.8 31.9 7.8
21.2 6.1 24.2 6.8 73 C.sub.3H.sub.9Si* 92.5 3.0 80.6 2.9 72.3 7.7
75.3 11.4 63 3.4 55.8 2.1 147 C.sub.5H.sub.15OSi.sub.2* 27.2 3.9
17.3 1.2 20.4 4.3 16.1 1.9 21.7 3.1 16.3 1.7 207
C.sub.5H.sub.15O.sub.3Si.sub.3* 6.05 0.74 3.71 0.18 4.51 0.55 3.54
0.37 5.31 0.59 4.08 0.28 647 C.sub.42H.sub.64PO.sub.3 1.61 1.65
1.09 1.30 0.325 0.307 nd ~ 0.868 1.31 0.306 0.334
TABLE-US-00011 TABLE 11 Normalized Mean Intensities of Various
Negative Ions of Interest (Normalized relative to total ion counts
.times. 10000) P-1e P-5e P-10e P-30e P-70e P-100e m/z species Mean
.sigma. Mean .sigma. Mean .sigma. Mean .sigma. Mean .sigma. Mean
.sigma. 13 CH 1950 72 1700 65 1870 91 1880 35 2000 46 2120 102 25
C.sub.2H 154 47 98.8 36.3 157 4 230 17 239 22 224 19 19 F 25.4 1
24.3 1.4 74.3 18.6 40.6 14.9 25.6 1.9 21.5 2 35 Cl 39.2 13.5 38.7
3.5 46.7 5.4 67.6 6.2 45.1 2.9 32.9 10.2 26 CN 71.9 18.9 6.23 2.61
28.1 10.1 34.2 29.2 57.3 28.9 112 60 42 CNO 0.572 0.183 0.313 0.077
0.62 0.199 1.29 0.2 1.37 0.55 1.38 0.28 46 NO.sub.2 0.331 0.057
0.596 0.255 0.668 0.149 1.44 0.19 1.92 0.29 0.549 0.1
TABLE-US-00012 TABLE 12 ToF-SIMS Parameters Instrument Conditions:
Instrument: PHI TRIFT II Primary Ion Source: .sup.69Ga Primary Ion
Beam Potential: 12 kV + ions 18 kV - ions Primary Ion Current (DC):
2 na for P#E samples 600 pA for P132 samples Energy Filter/CD:
Out/Out Masses Blanked: None Charge Compensation: On
[0132] ToF-SIMS uses a focused, pulsed particle beam (typically Cs
or Ga) to dislodge chemical species on a materials surface.
Particles produced closer to the site of impact tend to be
dissociated ions (positive or negative). Secondary particles
generated farther from the impact site tend to be molecular
compounds, typically fragments of much larger organic
macromolecules. The particles are then accelerated into a flight
path on their way towards a detector. Because it is possible to
measure the "time-of-flight" of the particles from the time of
impact to detector on a scale of nano-seconds, it is possible to
produce a mass resolution as fine as 0.00.times. atomic mass units
(i.e. one part in a thousand of the mass of a proton). Under
typical operating conditions, the results of ToF-SIMS analysis
include: a mass spectrum that surveys all atomic masses over a
range of 0-10,000 amu, the rastered beam produces maps of any mass
of interest on a sub-micron scale, and depth profiles are produced
by removal of surface layers by sputtering under the ion beam.
Negative ion analysis showed that the polymer had increasing
amounts of CNO, CN, and NO.sub.2 groups.
Example 7
X-Ray Photoelectron Spectroscopy (XPS)/Electron Spectroscopy for
Chemical Analysis (ESCA)
[0133] X-Ray Photoelectron Spectroscopy (XPS) (sometimes called
"ESCA") measures the chemical composition of the top five
nanometers of surface; XPS uses photo-ionization energy and
energy-dispersive analysis of the emitted photoelectrons to study
the composition and electronic state of the surface region of a
sample. X-ray Photoelectron spectroscopy is based upon a single
photon in/electron out. Soft x-rays stimulate the ejection of
photoelectrons whose kinetic energy is measured by an electrostatic
electron energy analyzer. Small changes to the energy are caused by
chemically-shifted valence states of the atoms from which the
electrons are ejected; thus, the measurement provides chemical
information about the sample surface.
TABLE-US-00013 TABLE 13 Atomic Concentrations (in %).sup.a,b Atom
Sample ID C O Al Si P132 (Area1) 57.3 39.8 1.5 1.5 P132 (Area2)
57.1 39.8 1.6 1.5 P132-10 (Area 1) 63.2 33.5 1.7 1.6 P132-10 (Area
2) 65.6 31.1 1.7 1.7 P132-100 (Area 1) 61.2 36.7 0.9 1.2 P132-100
(Area 2) 61 36.9 0.8 1.3 .sup.aNormalized to 100% of the elements
detected. XPS does not detect H or He.
TABLE-US-00014 TABLE 14 Carbon Chemical State (in % C) Sample ID
C--C, C--H C--O C.dbd.O O--C.dbd.O P132 (Area 1) 22 49 21 7 P132
(Area 2) 25 49 20 6 P132-10 (Area 1) 34 42 15 9 P132-10 (Area 2) 43
38 14 5 P132-100 (Area 1) 27 45 15 9 P132-100 (Area 2) 25 44 23
9
TABLE-US-00015 TABLE 15 Atomic Concentrations (in %).sup.a,b Atom
Sample ID C O Al Si Na P-1e (Area 1) 59.8 37.9 1.4 0.9 ~ P-1e (Area
2) 58.5 38.7 1.5 1.3 ~ P-5e (Area 1) 58.1 39.7 1.4 0.8 ~ P-5e (Area
2) 58.0 39.7 1.5 0.8 ~ P-10e (Area 1) 61.6 36.7 1.1 0.7 ~ P-10e
(Area 2) 58.8 38.6 1.5 1.1 ~ P-50e (Area 1) 59.9 37.9 1.4 0.8
<0.1 P-50e (Area 2) 59.4 38.3 1.4 0.9 <0.1 P-70e (Area 1)
61.3 36.9 1.2 0.6 <0.1 P-70e (Area 2) 61.2 36.8 1.4 0.7 <0.1
P-100e (Area 1) 61.1 37.0 1.2 0.7 <0.1 P-100e (Area 2) 60.5 37.2
1.4 0.9 <0.1 .sup.aNormalized to 100% of the elements detected.
XPS does not detect H or He. .sup.bA less than symbol "<"
indicates accurate quantification cannot be made due to weak signal
intensity.
TABLE-US-00016 TABLE 16 Carbon Chemical State Table (in % C) Sample
ID C--C, C--H C--O C.dbd.O O--C.dbd.O P-1e (Area 1) 29 46 20 5 P-1e
(Area 2) 27 49 19 5 P-5e (Area 1) 25 53 18 5 P-5e (Area 2) 28 52 17
4 P-10e (Area 1) 33 47 16 5 P-10e (Area 2) 28 51 16 5 P-50e (Area
1) 29 45 20 6 P-50e (Area 2) 28 50 16 5 P-70e (Area 1) 32 45 16 6
P-70e (Area 2) 35 43 16 6 P-100e (Area 1) 32 42 19 7 P-100e (Area
2) 30 47 16 7
TABLE-US-00017 TABLE 17 Analytical Parameters Instrument: PHI
Quantum 2000 X-ray source: Monochromated Alk.sub..alpha. 1486.6 eV
Acceptance Angle: .+-.23.degree. Take-off angle: 45.degree.
Analysis area: 1400 .times. 300 .mu.m Charge Correction: C1s 284.8
eV
[0134] XPS spectra are obtained by irradiating a material with a
beam of aluminum or magnesium with X-rays while simultaneously
measuring the kinetic energy (KE) and number of electrons that
escape from the top 1 to 10 nm of the material being analyzed (see
analytical parameters, Table 17). The XPS technique is highly
surface specific due to the short range of the photoelectrons that
are excited from the solid. The energy of the photoelectrons
leaving the sample is determined using a Concentric Hemispherical
Analyzer (CHA) and this gives a spectrum with a series of
photoelectron peaks. The binding energy of the peaks is
characteristic of each element. The peak areas can be used (with
appropriate sensitivity factors) to determine the composition of
the materials surface. The shape of each peak and the binding
energy can be slightly altered by the chemical state of the
emitting atom. Hence XPS can provide chemical bonding information
as well. XPS is not sensitive to hydrogen or helium, but can detect
all other elements. XPS requires ultra-high vacuum (UHV) conditions
and is commonly used for the surface analysis of polymers,
coatings, catalysts, composites, fibers, ceramics,
pharmaceutical/medical materials, and materials of biological
origin. XPS data is reported in Tables 13-16 above.
Example 8
Fourier Transform Infrared (FT-IR) Spectrum of Irradiated and
Unirradiated Samples
[0135] FT-IR analysis was performed on a Nicolet/Impact 400. The
results indicate that samples P132, P132-10, P132-100, P-1e, P-5e,
P-10e, P-30e, P-70e, and P-100e are consistent with a
cellulose-based material having carboxylic acid groups.
[0136] FIG. 12 is an infrared spectrum of Kraft board paper sheared
according to Example 4, while FIG. 13 is an infrared spectrum of
the Kraft paper of FIG. 12 after irradiation with 100 MRad of gamma
radiation. The irradiated sample shows an additional peak in region
A (centered about 1730 cm.sup.-1) that is not found in the
un-irradiated material. Of note, an increase in the amount of a
carbonyl absorption at .about.1650 cm.sup.-1 was detected when
going from P132 to P132-10 to P132-100. Similar results were
observed for the samples P-1e, P-5e, P-10e, P-30e, P-70e, and
P-100e.
[0137] The alfalfa samples showed a small peak present at 1720
cm.sup.-1 in the untreated sample, which grows to the most dominant
peak in the A-50e spectrum.
Example 9
Proton and Carbon-13 Nuclear Magnetic Resonance (.sup.1H-NMR and
.sup.13C-NMR) Spectra of Irradiated and Unirradiated Samples
Sample Preparation
[0138] The samples P132, P132-10, P132-100, P-1e, P-5e, P-10e,
P-30e, P-70e, and P-100e were prepared for analysis by dissolution
with DMSO-d.sub.6 with 2% tetrabutyl ammonium fluoride trihydrate.
The samples that had undergone lower levels of irradiation were
significantly less soluble than the samples that had undergone
higher irradiation. Unirradiated samples formed a gel in this
solvent mixture, but heating to 60.degree. C. resolved the peaks in
the NMR spectra. The samples having undergone higher levels of
irradiation were soluble at a concentration of 10% wt/wt.
Analysis
[0139] .sup.1H-NMR spectra of the samples at 15 mg/mL showed a
distinct very broad resonance peak centered at 16 ppm. This peak is
characteristic of an exchangeable --OH proton for an enol and was
confirmed by a "d.sub.2O shake." Model compounds (acetylacetone,
glucuronic acid, and keto-gulonic acid) were analyzed and made a
convincing case that this peak was indeed an exchangeable
proton.
[0140] The carboxylic acid proton resonances of the model compounds
were similar to what was observed for the treated cellulose
samples. These model compounds were shifted up field to .about.5-6
ppm. Preparation of P-100e at higher concentrations (.about.10%
wt/wt) led to the dramatic down field shifting to where the
carboxylic acid resonances of the model compounds were found
(.about.6 ppm). These results lead to the conclusion that this
resonance is unreliable for characterizing this functional group,
however the data suggests that the number of exchangeable hydrogens
increases with increasing irradiation of the sample. Also, no vinyl
protons were detected.
[0141] The .sup.13C NMR spectra of the samples confirm the presence
of a carbonyl of a carboxylic acid. This new peak (at 168 ppm) is
not present in the untreated samples (FIG. 12). A .sup.13C NMR
spectrum with a long delay allowed the quantitation of the signal
for P-100e (FIG. 14). Comparison of the integration of the carbonyl
resonance to the resonances at approximately 100 ppm (the C1
signals) suggests that the ratio of the carbonyl carbon to C1 is
1:13.8 or roughly 1 carbonyl for every 14 glucose units. The
chemical shift at 100 ppm correlates well with glucuronic acid.
[0142] The .sup.13C NMR spectrum for A-50E (166,000 scans; 38 h)
shows aromatic carbons of lignin (.about.130 ppm) and also shows
multiple carbonyl resonances around 170 ppm. The .sup.1H NMR
clearly shows the aromatic signals from lignin.
Manual Titration
[0143] Samples P-100e and P132-100 (1 g) were suspended in
deionized water (25 mL). The indicator alizarin yellow was added to
each sample with stirring. P-100e was more difficult to wet. Both
samples were titrated with a solution of 0.2M NaOH. The end point
was very subtle and was confirmed by using pH paper. The starting
pH of the samples was .about.4 for both samples. P132-100 required
0.4 milliequivalents of hydroxide, which gives a molecular weight
for the carboxylic acid of 2500 amu. If 180 amu is used for a
monomer, this suggests there is one carboxylic acid group for 13.9
monomer units. Likewise, P-100e required 3.2 milliequivalents of
hydroxide, which calculates to be one carboxylic acid group for
every 17.4 monomer units.
Potentiometric Titration Analysis
[0144] A potentiometer (Metrohm Ion Analysis 794 Basic Titrino) was
used to measure the electrode potential of sample solutions and
therefore an accurate titration analysis based on a redox reaction
was achieved. The potential of the working electrode will suddenly
change as the endpoint is reached.
Results
[0145] P-30E had one carboxylic acid per 57 saccharide units. P-70E
had one carboxylic acid unit per 27 saccharide units. P-100E had
one carboxylic acid per 22 saccharide units.
Conclusions
[0146] The C-6 carbon of cellulose appears to be oxidized to the
carboxylic acid (a glucuronic acid derivative) and this oxidation
is surprisingly specific. This oxidation is in agreement with the
IR band that grows with irradiation at .about.1740 cm.sup.-1, which
corresponds to an aliphatic carboxylic acid. The titration results
are in agreement with the quantitative .sup.13C NMR. The increased
solubility of the sample with the higher levels of irradiation
correlates well with the increasing number of carboxylic acid
protons. A proposed mechanism for the degradation of "C-6 oxidized
cellulose" is provided below in Scheme 1.
##STR00002##
Other Embodiments
[0147] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *