1. 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 1

2. 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. 2

3. 1 - Introduction 5

4. 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 6

5. Figure 1- Molecular structure of cellulose.11
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 7

6. Examples 8 Cellulosic 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 8

7. Amine and counter ion dissolution
ac sin γ projection;
ab projection 2
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
Figure 2 – Swollen cellulose – crystal structure 9

8. Amine and metal salt association
Ionic interactions assisting dissolution
Figure 3 – Coordination of ED and KSCN in solution9 Frey 10

9. 2 - Development of cellulose blend membranes11

10. 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
Figure 4 – Porous cellulose membrane12 12

11. 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 13

12. Simple setup for dissolution, paddle stirrer apparatus
Objective: Dissolution of cellulose and starch or protein as a blend50)
Simple setup for dissolution, paddle stirrer apparatus
Figure 5 - 7% free flowing ED/KSCN cellulose (DP = 450) solution
Figure 6 – Dissolution apparatus 14

13. Microscopic views of dissolution
Table 1 - Different swelling and dissolution mechanisms for cotton and wood fibers in NMMO – water mixtures at various water contents.3 15

14. 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. 34

15. Table 2 -Types of proteins used
Optimum Percent
Brim Soy Protein (USDA)
~50
Profam 974 Isolate
40-50% 35

16. 3 - Cellulose and proteins blended in solution to make membranes47

17. 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) 48

18. Brim and Profam 974 made best quality membranes
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. 49

19. 4 – Characterization of cellulose / soy protein blend membranes50

20. SEM cross section micrographs of 50/50 cellulose – soy protein blends – Compatible!
Figure 7 – 50/50 Cellulose/brim membrane, 5000x
Figure 8 – 50/50 Cellulose/Profam 974
membrane, 5000x 51

21. Figure 9 - Cellulose membrane: Onset 332º C, end 371º C, ash about 28%
TGA Analysis - cellulose membrane compared to cellulose/brim soy protein blend
100
100
Mass % 30
Figure 9 - Cellulose membrane: Onset 332º C, end 371º C, ash about 28% 30
20o C
710o C
Figure 10 - Cellulose / brim blend membrane: Onset 241º C, end 342º C, ash about 28%
20o C
710o C 52

22. TGA Analysis - cellulose membrane compared to cellulose/Profam 974 soy protein blend
100
100
Mass % 30 30
Figure 11 - Cellulose membrane: Onset 332º C, end 371º C, ash level about 28%
20o C
710o C
Figure 12 - Cellulose / Profam 974 blend membrane: Onset 284º C, end 344º C, ash level about 9%
20o C
710o C 53

23. Table 8 - Comparison of TGA results between membranes
Table 3 - Summary of TGA results for soy protein / cellulose blend membranes
Materials
Start temperature (ºC)
Onset temperature(s) (ºC)
Char 710º C (%)
Cellulose fiber
242
350 11
Cellulose membrane
257
332 28
Profam 974
189
276 27
Brim soy protein
193, 285
235, 310 25
Cellulose / Profam 974 mixed
185
290, 362 18
Cellulose / Profam 974 membrane
200
283 9
Cellulose / brim mixed
201, 280
234, 355 19
Cellulose / brim membrane
178
241
Table 8 - Comparison of TGA results between membranes 54

24. 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 θ
Figure 13 – Cellulose membrane
Figure 14 – Cellulose / Profam 974 membrane 55

25. 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
Notice
Notice
Figure 15 – Cellulose / Brim blend
Figure 16 – Cellulose / Profam 974 blend 56

26. Tensile Properties Summary
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 membrane
157 ± 52
3.2 ± 1.6
27 ± 12
0.029 ± 0.003
Cellulose / Profam 974 membrane
200 ± 75
4.7 ± 1.2
16 ± 8.0
0.026 ± 0.001
Cell / PF 40%
220 ± 53
5.0 ± 2.0
29 ± 12
Cell / PF 30%
204 ± 74
4.3 ± 2.3
0.031 ± 0.005
Cell / PF 20%
195 ± 69
2.4 ± 1.8
20 ± 12
0.034 ± 0.003 57

27. Physical Properties Summary
Table 5 – Comparison of water absorbency for soy blend membranes 57

28. 5 – Later work at NCSU 59

29. 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. 60

30. 6 – Coming work at Nazarbayev University Brief Discussion61

31. Conclusions New 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. 62

32. 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. 63

33. 7 - References 64

34. Ott . Cellulose and cellulose derivatives : Molecular characterization and its application. Burlington: Elsevier; 1954.
Khare VP, Greenberg AR, Kelley SS, Pilath H, Roh IJ, Tyber J. Synthesis and characterization of dense and porous cellulose films. J Appl Polym Sci 2007;105(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.
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.
Fink H, Weigel P, Purz HJ, Ganster J. Structure formation of regenerated cellulose materials from NMMO-solutions. Progress in Polymer Science ;26(9):
Swatloski RP, Spear SK, Holbrey JD, Rogers RD. Dissolution of cellulose with ionic liquids. J Am Chem Soc 2002;124(18):
Zhang . 1-allyl-3-methylimidazolium chloride room temperature ionic liquid: A new and powerful non-derivatizing solvent for cellulose. Macromolecules 2005;38(20):8272.
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 /29/1985
Frey M, Li L, Xiao M, Gould T. Dissolution of cellulose in ethylene diamine/salt solvent systems. Cellulose /29;13(2):
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.
Metzger J. Carbohydrate structures
Lee HJ. Novel cellulose solvent system and dry jet wet spinning of Cellulose/ED/KSCN solutions. Raleigh, NC: North Carolina State University; Available from: unrestricted 65

35. 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 66