Biopolymers in Textile Industry Dr. Asim Kumar Roy Choudhury, Principal, Gargi Memorial Institute of Technology, Baruipur, Kolkata 700144 (W.B.) Ex-Professor and HOD, (Textile), Govt. College of Engg. and Textile Technology, Serampore (W.B.) e-mail:
[email protected]
Introduction The biopolymers have been considered in the 1940s and Henry Ford used these biopolymers in the construction of a car. Biopolymers are produced by biological systems (i.e. microorganisms, plants and animals), or chemically synthesized from biological starting materials (e.g. sugars, starch, natural fats or oils, etc.).They are more biodegradable than vegetable or animal derived natural fibres. Biopolymers will account for just over 1% of polymers by 2015 (Doug, 2010). However, the expected growth is 3-4 times in the coming 7-8 years. Advantages of biopolymers • They are fully biobased. • Much lower “oil (petroleum)” is needed for production • Lower amount of green house gases emits during their production.
Ingeo®
(Polylactic acid (PLA) from Natureworks) requires 60% less greenhouse gases and 50% less non-renewable energy than other polymers (Ditty, 2013). Disadvantages of biopolymers •
The competition for biological sources of food and fuel
•
Additional sorting during recycling to avoid contamination.
•
Performance still inferior than oil based polymers – poorer heat and moisture resistance.
Application of biopolymers •
Drug delivery systems (medical field),
•
Wound closure and healing products (medical field),
•
Surgical implant devices (medical field).
•
Bioresorbable scaffolds for tissue engineering.
•
Food containers, soil retention sheeting, agriculture film, waste bags and packaging material in general.
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•
Non-woven biopolymers can also be used in agriculture, filtration, hygiene and protective clothing.
Biopolymers with high potential •
Starch based polymers (packaging)
•
Poly Lactide - PLA
•
Polyhydroxyalkanoates (PHA)/ Polyhydroxybutyrate (PHB)
•
(co)PA – (castor oil based - PA11)
•
Polybutylene succinate (PBS) and biopolyester based copolymers
•
Polyethylene Furanoate (PEF) - alternative for PET, made from two building blocks, Furandicarboxylic acid (FDCA) and Mono Ethylene Glycol (MEG).
Methods of Manufacture The methods for preparing bio-based polymers from renewable resources are: •
Extraction and separation of agricultural resources.
•
Partial modification of natural bio-based polymers (e.g., starch)
•
Production by microorganism (fermentation)/conventional chemistry followed by polymerization (e.g., polylactic acid, polybutylene succinate)
•
Direct bacterial fermentation processes (e.g., polyhydroxyalkanoates).
Classification of biopolymers •
Polynucleotides (RNA and DNA), which are long polymers composed of 13 or more nucleotide monomers;
•
Polypeptides, which are short polymers of amino acids; and
•
Polysaccharides, which are often linear bonded polymeric carbohydrate. This group includes alginates, Microbial cellulose ( MC ), Chitin and Chitosan,
Soybean fibre Soybean fibre is a man-made regenerated protein fibre from soybean protein blended with PVA. It is biodegradable, non-allergic, and micro-biocidal. The clothing made from the soy fibre is less durable but has a soft, elastic handle. Soybean protein is a globular protein and it has to undergo denaturation by alkali/heat/enzyme and degradation in order to convert the protein solution into a spinnable dope. Poly(alkylenedicarboxylate) polyesters (APDs) Monomers for aliphatic APDs can be petroleum derived (i.e. not renewable) or biomass derived (i.e. renewable), the former being the major route. Both can be prepared to the same degree of purity, but the later is still costlier. 2
Common dicarbo oxylic and diol monomers found in APDs arre shown in Figure 1. They include e succinicc acid (SA A), adipicc acid (AA),
ethylene e
1,4buta anediol
glycoll (1,4BD).
(EG)
and
Polybu utylene
succina ate (PBS) is an aliphatic pollyester with similar prop perties to those of PET. PBS is producced by condensatio c on of d 1,4-butan nediol. succiniic acid and PBS iss a semicryystalline polyester p w a melting point higher with h than n that of PLA. P Its mecha anical and thermal t pro operties de epend on the t crystal structure a and the de egree of crystalllinity. The e Tg is approximat a tely −32°C C, and th he melting g tempera ature is approxximately 11 15°C. In co omparison with PLA, PBS is to ougher in nature butt with a lower rigidity r and Young's modulus m (B Babu et al., 2013) Biosucccinic acid (SA) is produced directly d by fermentation of bioe engineered d yeast and E.. coli. Cattalytic hydrogenation n of biosuccinic acid d produces 1,4 buta anediol, which can also be b produced by ferm mentation. Bioethylene glycol is produce ed from bioethyylene, a product p off catalytic dehydration of ferm mentation derived ethanol. e Bioadip pic acid ca an be produ uced by a number of fermentation based processes s. Applica ation: Aliphatic polyy(alkylened dicarboxyla ates) are used in p polyurethan nes for coating gs, adhesivves and fo oams; flexxible packa aging; agriicultural films; comp postable bags; and in ble ends and composite es with otther bioba ased polym mers to enhance propertties (Gotro o, 2013). Bio-po olyamide (Nylon) ( Castorr oil has been b a no on-food cro op source of biopolyymers. Po olyamide 11 1 from castor oil was pa atented in 1944 1 by Frrench scien ntists and from 2004 4 it is marketed by Arkema a as Rilsan n for sportw wear. Tora ay and Rad dici are no ow marketin ng anotherr castor oil-derived polyam mide, PA 6-10. 6 Sofia a launched d a hybrid polyamide p fibre, Gre eenfil by texturissing 70% synthetic PA 6 and 30% bioso ourced PA A 10. A gre eenfil sock is 5-10 times stronger, s but 2-3 time es costlier too (Sofia, 2012) Bio-po olyethylene Polyeth hylene (PE E) is an im mportant engineering g polymer traditionally produce ed from fossil resources. r Bio-based d polyethyylene has exactly e the e same ch hemical, physical,
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and mechanical properties as petrochemical polyethylene. The sequence for biological method is as follows: Fermentation of sugarcane/sugar beet/starch crop Æ bioethanol Æ distilled at high temperature over a solid catalyst Æ ethylene Æ microbial PE or green PE Biodegradable Polyurethanes (PURs) PURs are known for toughness, durability, biocompatibility, and biostability. Unlike polyester derivatives, polyether-based PURs are quite resistant to degradation by microorganisms. Biodegradable PURs employed as thermoplastics are basically synthesized using a diisocyanate, a diol, and a chain-extension agent. The first representative example avoiding diisocyanate is the reaction between a cyclic carbonate and an amine rendering the urethane bond. In particular, the polyaddition reaction between L-lysine and a bi-functional five-member cyclic carbonate in the presence of a strong base. Some have reported the enzymatic synthesis of PEUs by enzymatic polyesterification (Lendlein and Sisson, 2011). Polylactic acid (PLA) PLA is known since 1845 but not commercialized until early 1990. It is the only meltprocessable fibre from annually renewable natural resources such as corn starch (in the United States), tapioca products (roots, chips or starch mostly in Asia) or sugar cane (in the rest of world). It is a thermoplastic, aliphatic polyester similar to synthetic polyethylene terephthalate (PET). The sequence of manufacture steps is as follows: Corn Æ starch Æ unrefined dextrose Æ fermentation Æ D- and L-lactic acid Æ monomer production Æ D-, L- and meso-lactides Æ polymer (PLA) production Æ polymer modification Æ fibre, film, plastic, bottle manufacture. The polymerization reaction is shown in Equation 1.
(1)
Lactic acid Lactide Polylactic acid PLA has high strength, good drape, wrinkle- and UV light- resistance properties. Its melting point is ± 170 °C and density is 1.25 g/cm³. The limiting oxygen index is 25 higher than PET and much higher PP. PLA, therefore, possess
reduced
flammability, less flame retardants. Water uptake is low (0.4 -0.6%) higher than PET and PP. it possess good durability under a range of conditions. 4
Application: woven shirts (ironability), microwavable trays, hot-fill applications and even engineering plastics. Biomedical applications include as sutures, stents, dialysis media and drug delivery devices. PLA can be used for rigid thermoforms, films, labels, and bottles, but not for hot-fill containers or gaseous drinks such as beer or sodas. Bacterial Polyesters The
bacterial
polyesters,
hydroxybutyrate
(P3HB)
by microorganisms.
polyhydroxyalkanoates as
compound
polyhydroxybutyrate
copolymer
named
developed
first
homologue
with
(Figure
2)
poly-(R)-3produced
Bacterial
storage (PHBV)
the
(PHAs)
“Biopol”
by
Bioproducts
is
Zeneca through
fermentation of PH3B followed by copolymerisation with PHV. It is
high
molecular
weight
polyester and thermoplastic (melts at 1800C) and can be melt spun into biocompatible and biodegradable fibres suitable for surgical use. Advantages include production from fully renewable resources, fast and complete biodegradability and excellent strength and stiffness. The disadvantages are high thermal degradability, brittleness and high price (Chod´ak, 2009). Sodium alginate Fibre Sodium alginate is a polymeric acid, composed of two monomer units (i) L-guluronic acid( G) (ii) Dmannuronic acid (M) (Figure 3) It is non toxic and non irritant. Alginate fibre generates a moist healing environment and is used for wound dressing. Calcium alginate is created by adding aqueous calcium chloride to aqueous sodium alginate.
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Chitin and chitosan Both polysaccharides may be regarded as derivatives of cellulose, where chitin bears an acetamido group and chitosan bears a aminogroup instead of the C - 2 hydroxyl
functionality.
Currently,
the
commercial source of chitin is shrimp shells. But the polymer also occurs in the shells of crabs and lobsters. Derivatives of chitin have been used to impart antistatic and soil-repellent finishing to the textiles. While chitin is used in printing and finishing preparations, while chitosan is able to remove dyes from discharge water. Both have remarkable contribution to medical related textile sutures, threads and fibres. Conclusions Biopolymers are very important in all aspects of medicine, surgery and healthcare and extend of application on which the materials used because of the versatility of biopolymer. Oil is the fuel that drives the global economy, but oil reserves are going down. And there are major concerns about the future because of our great dependency on oil and its impact on the environment. References: Babu
R.
P.
et
al.
(2013).
Progress
in
Biomaterials,
2:8,
http://www.progressbiomaterials.com/content/2/1/8) Chod´ak I. (2009). Sustainable Textiles: Life Cycle and Environmental Impact, R.S. Blackburn, ed., Woodhead, Cambridge, UK, p.88.). Ditty Sarah (2013). 7 biopolymer eco fabrics you need to know about, http://source.ethicalfashionforum.com/, 12 August). Doug S. (2010) Bioplastics: technologies and global markets. BCC research reports PLS050A. Gotro J. (2013). Aliphatic Poly(alkylenedicarboxylate) Polyesters: Organic or Not Organic? Polymer Innovation Blog, http://polymerinnovationblog.com/ , April 15) Lendlein A. and Sisson A. (2011). Handbook of Biodegradable Polymers. WileyVSH, Weinheim, Germany. Sofia
(2012).
New
yields
in
castor
file:///H:/biopolymer%20conf/
6
oil
polyamides.
WSA,
May-June,
