Rebirth of Bio-based Polymer Development

1. Rebirth of Bio-based Polymer Development Dr. Shelby F. Thames The University of Southern Mississippi

2. Applications • Coatings • Fibers • Plastics • Adhesives • Cosmetics • Oil Industry • Paper • Textiles/clothing • Water treatment • Biomedical • Pharmaceutical • Automotive • Rubber

3. Polymers • Polymers are broadly classified into: • Synthetic • Natural • Synthetic polymers are obtained via polymerization of petroleum-based raw materials through engineered industrial processes using catalysts and heat

4. Polyethylene Polypropylene Polytetrafluoroethylene (Teflon®) Polyvinylchloride Polyvinylidenechloride Polystyrene Polyvinylacetate Polymethylmethacrylate (Plexiglas®) Polyacrylonitrile Polybutadiene Polyisoprene Polycarbonate Polyester Polyamide (nylons) Polyurethane Polyimide Polyureas Polysiloxanes Polysilanes Polyethers Synthetic Polymers

5. Natural Polymers • Natural polymeric materials have been used throughout history for clothing, decoration, shelter, tools, weapons, and writing materials • Examples of natural polymers: • Starch • Cellulose (wood) • Protein • Hair • Silk • DNA and RNA • Horn • Rubber

6. Chronological Development • Natural resins From early history • Modified phenolic 1910 • Nitrocellulose 1920 • Air-drying oil-modified polyesters 1927 • Urea-formaldehyde polymers 1929 • Chlorinated rubber 1930 • Acrylates 1931 • Cellulose derivatives 1935 • Polystyrene 1937 • Melamine formaldehyde 1939 • Polytetrafluoroethylene 1946 • Polyethylene 1946

7. Biopolymers • Biopolymers are obtained via polymerization of biobased raw materials through engineered industrial processes • The raw materials of biopolymers are either isolated from plants and animals or synthesized from biomass using enzymes/ microorganisms

8. Polyesters Polylactic acid Polyhydroxyalkanoates Proteins Silk Soy protein Corn protein (zein) Polysaccharides Xanthan Gellan Cellulose Starch Chitin Polyphenols Lignin Tannin Humic acid Lipids Waxes Surfactants Specialty polymers Shellac Natural rubber Nylon (from castor oil) Examples of Biopolymers

9. Why Biopolymers? • Fossil fuels (oil, gas, coal) are in finite supply and alternative renewable sources of raw materials are needed • USDA's Bioproduct Chemistry & Engineering Research Unit focuses on creating new polymer technologies in which underutilized components of crops and their residues are processed into value-added biobased products. • Most synthetic polymers are not biodegradable

10. Sustainability • Sustainability is defined as a development that meets the needs of the present world without compromising the needs of future generations. Agricultural products offers this capability. World Commission on Environment and Development

11. Biodegradable Polymers • Polymers such as polyethylene and polypropylene persist in the environment for many years after their disposal • Physical recycling of plastics soiled by food and other biological substances is often impractical and undesirable • Biodegradable polymers break down in a bioactive environment to natural substances by enzymatic processes and/or hydrolysis

12. Where are BiodegradablePolymers Needed? • Packaging materials (e.g., trash bags, loose-fill foam, food containers) • Consumer goods (e.g., egg cartons, razor handles, toys) • Medical applications (e.g., drug delivery systems, sutures, bandages, orthopedic implants) • Cosmetics • Coatings • Hygiene products

13. Biodegradable Polymers Market • Global consumption of biodegradable polymers increased from 14 million kg (30.8 million lbs) in 1996 to 68 million kg (149.6 million lbs) in 2001 • U.S. demand for biopolymers is expected to reach $600 million by 2005 according to a Freedonia Group study U.S. Congress, Office of Technology Assessment, Biopolymers: Making Materials Nature’s Way-Background Paper, OTA-BP-E-102 (Washington, DC: U.S. Government Printing Office, September 1993

14. Opportunities for Biodegradable Polymers: Vegetable Oils Oils are triglyceride esters of mixed fatty acids where R1, R2, and R3 are saturated or unsaturated fatty acids

15. Fatty Acid Composition of Vegetable Oils Oil Saturated Oleic Linoleic Linolenic Others Iodine Value Sunflower 10 30 60 - - 125 - 136 Soybean 14 30 50 6 - 120 - 141 Safflower 7 15 78 - - 140 - 150 Oiticica 10 6 6 - 78f 147 - 165 Chinese Melon 33 2 4 1 58g 120 - 130 Tung 4 7 9 - 80g 160 - 175 Linseed 8 20 19 52 - 165 - 202 Castor 3 7 5 - 85k 81 - 91 Coffee ? 9 46 - 45h,i,j 100 - 111 f) Licanic acid g) Eleostearic acid h) Palmitic i) Estearic j) Araquidic k) Ricinoleic acid

16. Unsaturated Fatty Acids in Vegetable Oils 9-Oleic Acid 9,12-Linoleic Acid 9,12,15-Linolenic Acid Ricinoleic Acid

17. Oil-Modified Polyesters • Oil-modified polyesters (alkyds) are synthesized by reacting oils, polyhydric alcohols, and polyfunctional acids • Single largest quantity of solvent-soluble polymers manufactured for use in surface coatings industry

18. Oil-Modified Polyesters (continued) • Oil-modified polyesters are classified into four categories based on their oil content: • Very long oil polyesters (>75%) • Used in printing inks and as plasticizers for nitrocellulose coatings • Long oil polyesters (60-75%) • Used in architectural and maintenance coatings as brushing enamels, undercoats, and primers • Medium oil polyesters (45-60%) • Used in anti-corrosive primers and general maintenance coatings • Short oil polyesters (<45%) • Used with amino resins in heat-cured OEM coatings

19. 2 + Dimer Acid Polyamides (R) • Long chain fatty acid dimers derived from vegetable oils are reacted with slight excess of primary amines to synthesize polyamides O H N H R N H 2 C O C O ( C H ) 2 7 ( C H ) 2 7 O O C H C H C H ( C H ) C O H H C 2 7 C H ( C H ) C N H R N H H C 2 7 2 C H H C C H H C C H C H C H C H C H ( C H ) C H 2 5 ( C H ) 2 5 ( C H ) C H 2 5 ( C H ) 3 C H 2 5 3 C H 3 C H 3

20. C H O O 3 + 2 H C C H C H O C O C H C H C H 2 2 2 2 C H 3 O H C H O H 3 H N R N C H C H C H O C O C H C H C H N R N H 2 2 2 2 2 2 H C H H 3 Dimer Acid Polyamides (continued) • Polyamide-epoxy systems are the workhorse of high performance protective coatings

21. Epoxidized Oils • Epoxidized oils are synthesized by reacting vegetable oils (typically soybean and linseed oils) with peracids or hydrogen peroxide • Epoxidized oils are employed as plasticizers for polyvinyl chloride and as high temperature lubricants

22. O [ ] O ( C H ) C n 2 5 Poly(e-caprolactone) • As early as 1973, it was shown that poly(e-caprolactone) degrades in bioactive environments such as soil • Poly(e-caprolactone) and related polyesters are water resistant and can be melt-extruded into sheets and bottles

23. O O [ ] H O C ( C H ) C O H 2 n Polyhydroxyalkanoates • Polyhydroxyalkanoates (PHA) accumulate as granules within cell cytoplasm • PHAs are thermoplastic polyesters with m.p. 50–180ºC (BiopolTM) • Properties can be tailored to resemble elastic rubber (long side chains) or hard crystalline plastic (short side chains)

24. PHA Production Raw materials Media preparation Fermentation Cell disruption Washing Centrifugation Drying PHA Carbon source Bacteria growth and polymer accumulation Polymer purification

25. PHB-V • Polyhydroxybutyrate – polyhydroxyvalerate (PHB-V) is formed when bacteria is fed a precise combination of glucose and propionic acid • PHB-Vhas properties similar to polyethylene but degrades into water and carbon dioxide under aerobic conditions

26. Starch • Starch is the principal carbohydrate storage product of plants • Starch is extracted primarily from corn; with lesser sources being potatoes, rice, barley, sorghum, and wheat • All starches are mixtures of two glucan polymers – amylose and amylopectin, at ratios that vary with the source

27. Starch (continued) • ~75% of industrial corn starch is made into adhesives for use in the paper industry • Corn starch absorbs up to 1,000 times its weight in moisture and is used in diapers (>200 million lb annually) • Starch-plastic blends are used in packaging and garbage bag applications U.S. Congress, Office of Technology Assessment, Biopolymers: Making Materials Nature’s Way-Background Paper, OTA-BP-E-102 (Washington, DC: U.S. Government Printing Office, September 1993

28. Starch (continued) • Starch blended or grafted with biodegradable polymers such as polycaprolactone are available in the form of films • Blends with more than 85% starch are used as foams in lieu of polystyrene

29. Cellulose • Cotton contains 90% cellulose while wood contains 50% cellulose • Cellulose derivatives are employed in a variety of applications • Carboxymethyl cellulose is used in coatings, detergents, food, toothpaste, adhesives, and cosmetics applications

30. Cellulose (continued) • Hydroxyethyl cellulose and its derivatives are used as thickeners in coatings and drilling fluids • Methyl cellulose is used in foods, adhesives, and cosmetics • Cellulose acetate is a plastic employed in packaging, fabrics, and pressure-sensitive tapes

31. Chitin • Chitin, a polysaccharide, is almost as common as cellulose in nature, and is an important structural component of the exoskeleton of insects and shellfish • Chitin and its derivative, chitosan, possess high strength, biodegradability, and nontoxicity • The principal source of chitin is shellfish waste

32. Chitosan • Chitosan forms a tough, water-absorbent, oxygen permeable, biocompatible films, and is used in bandages and sutures • Chitosan is used in cosmetics and for drug delivery in cancer chemotherapy • Chitosan carries a positive charge (cationic) in aqueous solution and is used as a flocculating agent to purify drinking water

33. Lactic Acid • Lactic acid is produced principally via microbial fermentation of sugar feedstocks • Variation in polymerization conditions and L- to D- isomer ratios permit the synthesis of various grades of polylactic acid • Polylactide polymers are the most widely used biodegradable polyesters

34. Polylactic Acid • Polylactic acid (PLA) degrades primarily by hydrolysis and not microbial attack • PLA fabrics have a silky feel and good moisture management properties (draws moisture away and keeps the wearer comfortable) • Copolymers of lactic acid and glycolic acid are used in sutures, controlled drug release, and as prostheses in orthopedic surgery

35. Polyamino Acids • Polyamino acids (polypeptides) are found in naturally occurring proteins • 20 amino acids form the building blocks of a variety of polymers • Polypeptides based on glutamic acid, aspartic acid, leucine, and valine are the most frequently used

36. Leucine Glutamic acid Aspartic acid Valine Amino Acid Structures

37. Polyamino Acids (continued) • Glutamic acid and aspartamic acid are hydrophilic whereas leucine and valine are hydrophobic in nature • Combination of these amino acids in different ratios permits the development of copolymers with varying rates of biodegradability (for use as drug delivery systems)

38. Polyamino Acids (continued) • Amino acid polymers are particularly attractive for medical applications since they are nonimmunogenic (i.e., do not produce any immune response in animals) • Homopolymers of aspartic acid and glutamic acid are water-soluble, biodegradable polymers

39. Protein • Soybeans are grown primarily for their protein content and secondarily for their oil • A 60-pound bushel of soybeans yields about 48 pounds of protein-rich meal and 11 pounds of oil • U.S. soybean production exceeded 2,500 million bushels in 2002 www.unitedsoybean.org

40. Soybean Protein • Soybean protein consists mainly of the acidic amino acids (aspartic and glutamic acids), and their amides, nonpolar amino acids (alanine, valine, and leucine), basic amino acids (lysine and arginine), and uncharged polar amino acid (glycine) Alanine Arginine Glycine

41. Soybean Protein (continued) • Soybean protein is available as soy protein concentrate, soy protein isolate, and defatted soy flour • Soybean protein is employed in paper coatings, with casein in adhesive formulations, wood bonding agents, and composites

42. Corn Protein • Corn protein (zein) is a bright yellow, water-insoluble powder • Zein forms odorless, tasteless, clear, hard, and almost invisible edible films, and is therefore used as coatings for food and pharmaceutical ingredients

43. Polyvinyl Alcohol • Polyvinyl alcohol is the only polymer with exclusively carbon atoms in the main chain that is regarded as biodegradable • Polyvinyl alcohol is used in textile, paper, and packaging industries

44. Sorona® • Sorona® is a biopolyester marketed by DuPont for use in fibers and fabrics and is based on 1,3-propanediol (derived from fermentation of corn sugar) • Sorona offers advantages over both nylon and PET by virtue of softer feel, better dyeability, excellent wash fastness, and UV resistance

45. Thames Research Group

46. Castor Acrylated Monomer Acrylate group reacts with growing polymer radicals Residual unsaturation provides mechanism for ambient cure Alkyl moieties provide internal plasticization

47. United States Marines Utilize USM Technology New fatigues are treated with a latex-based product

48. VOMM-Based Textile Latex • 12,000 Marine Corps uniforms are treated monthly by a Mississippi-based company • Over 100 new jobs created • 7,500 uniforms are being evaluated by the Air Force

49. USM Waterborne Water Repellant USM Soy-Based Waterborne Water Repellent Commercial Solvent-Based Water Repellent

50. Formaldehyde-Free Biodegradable Wood Composites • Renewable • Biodegradable • Formaldehyde-free • Environmentally-friendly