Presented by (click to enter name)

Development and characterization of compatible cellulose

and cellulose blended with soy protein membranes using a

novel solvent system

By

Eugene F. Douglass, MS, PhD

Department of Chemistry

Nazarbayev University, Astana, Kazakhstan

&

Richard Kotek, PhD

TECS, College of Textiles

North Carolina State University, Raleigh, NC USA

June 28, 2010

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Objectives - Reviewing briefly the literature, and previous work with

this system. To summarize the recent work developing

new fibers and membranes using our novel solvent

system.

To show the development of biopolymer blend cellulose

membranes, using previous work as a foundation.

To show the characterization of the membranes.

To extend the preliminary goals of the research into a

new creative area, developing brand new materials that

may have use in the membrane industry, and to

characterize these new materials.

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Presented by

1 - Introduction

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Layer of material which serves as a selective barrier

Barrier is between two or more phases

Remains impermeable to specific particles, molecules or

substances

Osmotic forces enable free flow of solvents

Some components are allowed passage into permeate stream

Others are retained and remain in the retentate stream

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Cellulosic sources Cellulose most abundant naturally occurring polymeric

raw material – very cheap raw material

Wood pulp, cotton, other plant fibers, or plant waste

Figure 1- Molecular structure of cellulose.11

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ExamplesCellulosic fibers and membranes

Natural cellulose fibers: cotton, linen, & flax

Regenerated cellulose: rayon fiber and film, cellophane film

Cellulose dissolved in a solvent: Lyocell fiber and film

Cellulose derivatives: nitrocellulose, celluloid, cellulose acetate fibers and films

Early solution methods – Regenerated cellulose: Cellulose xanthate is made, dissolved,

then regenerate the cellulose chemically.

Viscose process

Rayon

Problems: dangerous solvent, toxicity of waste material

Recent solution methods – Dissolve cellulose in a solvent system

Lyocell process – prime commercial process

Lyocell

Problems: solvent instability issues, expensive

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Amine and counter ion dissolution

Zn+2 > Li+ > Ca+2 > Mg+2 > Ba+2 > Na+ > NH4+ > K+

SCN- > I- > PO4-3 > Br- > Cl- > NO3

- > SO4-2 > ClO3

-

Order of decreasing swelling of cellulose 2

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Figure 2 – Swollen cellulose –

crystal structure

A) ac sin γ projection;

B) ab projection 2

Amine and metal salt association Ionic interactions assisting dissolution

+< 20mol%

> 20mol%

SCNK+

ED

A

ED

A

EDA

ED

A

NH2CH2CH2NH2

EDA

ED

A

dissociation

association

EDA=

cell-OH

dissolutioncell-OH= cellulose

K+

ED

A

ED

A

EDA

ED

A

EDA

ED

A

SCN

ED

A

ED

A

EDA

ED

A

EDA

ED

A

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Figure 3 – Coordination of ED and KSCN in solution9 Frey

Presented by

2 - Development of cellulose

blend membranes

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Previous work at North Carolina State University

Hyun Lee12 – developed cellulose fibers from this optimized solvent blend,

and did some basic membrane investigation

Possible porous membrane

Severe yellowing upon aging

Problems:

could not reproduce this structure using means described

Used non-reproducible method of casting

Used tape layers on glass rods

Draw down on glass plate, hard to remove

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Figure 4 – Porous cellulose

membrane12

Development of new casting process for reproducibility

Reproducibility is required

Casting table

Uniform casting bar

Cast on PET plastic film for ease of placing in coagulation bath

and removal of coagulated membranes

Obtained casting table and bars from Byk-Gardner

Obtained casting PET film and drawdown panels for

sample membranes

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Objective: Dissolution of cellulose and starch or protein as a

blend50)

Simple setup for

dissolution, paddle

stirrer apparatus

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Figure 5 - 7% free flowing ED/KSCN

cellulose (DP = 450) solution

Figure 6 – Dissolution apparatus

Microscopic views of dissolution

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Table 1 - Different swelling and dissolution mechanisms for cotton and wood fibers

in NMMO – water mixtures at various water contents.3

Background of invention of new

material Cellulose and starch are polysaccharides

Bond linkage of glucose units different

Solvent for cellulose works, perhaps would work for starch.

Discussion with Drs. Kotek, Venditti, and Pawlak: Can starch make

a membrane with this solvent system? No, could we do a blend??

Motivation Attempt blend with starch for membranes; success!

Based on success with starch; chitosan, chitin and soy protein were

also tried.

Both porous and nonporous membranes were obtained, this section

describes the development of cellulose blended with soy protein to

form a useful membrane.

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Table 2 -Types of proteins used

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Protein Optimum Percent

Brim Soy Protein (USDA) ~50

Profam 974 Isolate 40-50%

Presented by

3 - Cellulose and proteins

blended in solution to

make membranes

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Development of cellulose / soy protein blend

membranes

Based on success with Starches, we thought protein might work

First attempt with Brim Soy Protein isolate, received from USDA labs on NCSU

campus

Two protein types in the Brim blend

Dissolves well in solvent blend

ADM soy materials received from NC Soy Council

SAF soy protein

Archon F soy protein concentrate

Profam 974 soy protein isolate (comparable to Brim)

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Sample blend membranes made from each

protein, to determine best quality membranes.

Brim and Profam 974 made best quality

membranes

These were used for main characterization

Determine ideal mass ratios of Soy protein to

cellulose using Profam 974 at 40, 30 and 20%

by characterization of each mass percent

membrane.

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Presented by (click to enter name)

4 – Characterization of cellulose

/ soy protein blend membranes

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SEM cross section micrographs of 50/50 cellulose –

soy protein blends – Compatible!

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Figure 7 – 50/50 Cellulose/brim

membrane, 5000x

Figure 8 – 50/50 Cellulose/Profam

974

membrane, 5000x

TGA Analysis - cellulose membrane compared to cellulose/brim soy protein

blend

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Figure 9 - Cellulose membrane:

Onset 332º C, end 371º C, ash

about 28% Figure 10 - Cellulose / brim blend

membrane: Onset 241º C, end

342º C, ash about 28%

Mass %

20o C

20o C

710o C

710o C

100 100

3030

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Figure 11 - Cellulose membrane:

Onset 332º C, end 371º C, ash

level about 28%Figure 12 - Cellulose / Profam

974 blend membrane: Onset

284º C, end 344º C, ash level

about 9%

Mass %

20o C

20o C 710o C

710o C

100100

30 30

TGA Analysis - cellulose membrane compared to cellulose/Profam 974 soy protein blend

Table 3 - Summary of TGA results for soy protein / cellulose blend membranes

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Table 8 - Comparison of TGA results between membranesMaterialsStart temperature

(ºC)

Onset temperature(s)

(ºC)

Char level @ 710º C

(%)

Cellulose fiber 242 350 11

Cellulose

membrane 257 332 28

Profam 974 189 276 27Brim soy

protein 193, 285 235, 310 25

Cellulose /

Profam 974

mixed185 290, 362 18

Cellulose /

Profam 974

membrane200 283 9

Cellulose /

brim mixed 201, 280 234, 355 19

Cellulose /

brim

membrane178 241 28

Wide Angle X-ray Scattering of Profam 974 blend membrane

Cellulose II Structure Amorphous Structure

Peaks at 16,17 and 23 2θ Broad Peak at 20-22 2θ

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Figure 13 – Cellulose membrane Figure 14 – Cellulose / Profam 974

membrane

Wide Angle X-ray Scattering of Stretched Soy Protein blend membranes

Amorphous Structure Amorphous Structure

Peaks at around 14 and 21 2θ Around 14 and 21 2θ

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Figure 15 – Cellulose / Brim

blendFigure 16 – Cellulose / Profam

974 blend

NoticeNotice

Tensile Properties Summary

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Table 4 – Comparison of Tensile properties for soy blend membranes

Samples Tensile modulus

(kgf/mm2)

Failure stress

(kgf/mm2)

Failure strain

(%)

Thickness

(mm)

Cellulose

membrane 75 ± 12 2.5 ± 1.2 36 ± 12 0.047 ± 0.015

Cellulose /

brim

membrane157 ± 52 3.2 ± 1.6 27 ± 12 0.029 ± 0.003

Cellulose /

Profam 974

membrane200 ± 75 4.7 ± 1.2 16 ± 8.0 0.026 ± 0.001

Cell / PF

40% 220 ± 53 5.0 ± 2.0 29 ± 12 0.026 ± 0.001

Cell / PF

30% 204 ± 74 4.3 ± 2.3 27 ± 12 0.031 ± 0.005

Cell / PF

20% 195 ± 69 2.4 ± 1.8 20 ± 12 0.034 ± 0.003

Physical Properties Summary

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Table 5 – Comparison of water absorbency for soy blend membranes

Presented by

5 – Later work at

NCSU

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Presented by (click to enter name)

• Made blend fibers from

cellulose / waxy maize, and

cellulose / soy protein blends.

• Cross-linked cellulose and

cellulose blend membranes to

prevent falling apart in long

term water contact.

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Presented by

6 – Coming work at

Nazarbayev University

Brief Discussion

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ConclusionsNew dissolution process development:

Using a special solvent system of ED/KSCN in a 65/35

mass % ratio, functional porous and non-porous

membranes were produced that have comparable

physical properties to other methods of making cellulose

membranes.

New material development:

Using the same solvent system, soy protein was blended

with cellulose in the solution and cast to make functional

non-porous blend membranes, that are stronger than the

cellulose porous membranes developed earlier, and very

water absorbent.

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Conclusions Using the same solvent system, soy protein was blended

with cellulose to make functional non-porous blend

membranes, that are strong and even more water

absorbent than the blend membrane with starch.

The casting and drying processes were optimized to deal

with issues of shrinkage that causes wrinkling and

variable film thicknesses

Other polysaccharides (chitosan and chitin), and protein

(keratin from hair) were also used to make functional

blend membranes with cellulose, suggesting further

applications for this system, perhaps using wool will give

some interesting materials, both as membranes and

fibers.

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Presented by

7 - References

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1. Ott . Cellulose and cellulose derivatives : Molecular characterization and its application. Burlington:

Elsevier; 1954.

2. Khare VP, Greenberg AR, Kelley SS, Pilath H, Roh IJ, Tyber J. Synthesis and characterization of dense

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3. Cuissinat C, Navard P. Swelling and dissolution of cellulose part 1: Free floating cotton and wood fibres

in N-methylmorpholine-N-oxide-water mixtures. Macromolecular Symposia 2006;244(1):1.

4. Cuissinat C, Navard P. Swelling and dissolution of cellulose part II: Free floating cotton and wood fibres

in NaOH-water-additives systems. Macromolecular Symposia 2006;244(1):19.

5. Fink H, Weigel P, Purz HJ, Ganster J. Structure formation of regenerated cellulose materials from

NMMO-solutions. Progress in Polymer Science 2001 11;26(9):1473-524.

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Soc 2002;124(18):4974-5.

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derivatizing solvent for cellulose. Macromolecules 2005;38(20):8272.

8. Hafez MM, Pauls HW, inventors. Method for preparing thin regenerated cellulose membranes of high flux

and selectivity for organic liquids separations. Exxon Research and Engineering Co., editor. 4496456.

1985 1/29/1985

9. Frey M, Li L, Xiao M, Gould T. Dissolution of cellulose in ethylene diamine/salt solvent systems.

Cellulose 2006 04/29;13(2):147-55.

10. Cao Y. Preparation and properties of microporous cellulose membranes from novel cellulose/aqueous

sodium hydroxide solutions. Journal of Applied Polymer Science [Internet]. [revised 2006;102(1):920.

11. Metzger J. Carbohydrate structures

http://chemistry.gcsu.edu/~metzker/Common/Structures/Carbohydrates/

12. Lee HJ. Novel cellulose solvent system and dry jet wet spinning of Cellulose/ED/KSCN solutions.

Raleigh, NC: North Carolina State University; 2007. Available from: unrestricted

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8- Acknowledgements

North Carolina State University, College of Textiles

including

Drs. Richard Kotek, Peter Hauser and Alan Tonelli

Dr. Richard Venditti and Dr. Joel Pawlak, College of Natural

Resources

Chuck Mooney, Birgit Anderson and Theresa White

Nazarbayev University, Astana, Kazakhstan seed

funding to disseminate this work, and develop further

work

Drs. Kenneth Alibek SST, Sergey Mikhalovsky College of

Engineering

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