Biodegradable polymers lactic acid-based

Hiltunen, K., Sepp, J. V., It, M., Mika, H. The Biodegradation of Lactic Acid-Based Poly (ester-Urethanes)./. Environ. Polym. Degrad., 1997, 5,167-173. 

Hiltunen K, Seppala JV, Itavaara M, Harkonen M (1997) The biodegradation of lactic acid-based poly(ester-urethanes). J Environ Polym Degrad 5 167-173 Hossein AK, Seyed HJ, Ahmad A (2008) A review on homopolymer, blends, and nanocomposites of poly(trimethylene terephthalate) as a new addition to the aromatic polyesters class. Iran Polym J 17 19-38... 

The biodegradability of lactic acid-based polymers was studied under controlled composting conditions (according to future CEN EN 14046), and the quality of the compost was evaluated [24]. All the polymers biodegraded to over 90% of the positive control in six months, which is the limit set by the CEN standard. 

Tuominen I, Kylma I, Kapanen A., Venelampi O., Mvaara M., Seppfllfl X Biodegradation of lactic acid based polymers under controlled composting conditions and evaluation of the ecotoxico-logical impact. Biomacromolecules 3 (2002) 445. 

Tuominen, J., Kylma, J., Kapanen, A., Venelam-pi, O., Itavaara, M., and Seppala, J. (2002). Biodegradation of lactic acid based polymers under eontrolled eomposting eonditions and evaluation of the eeotoxicological impact. Biomacromolecules 3(3), 445 55. 

Nearly 95,000 tons of glucose and dextrose are produced by enzymatic liquefaction of starch, mainly tapioca (cassava). Since lactic acid-based biodegradable polymers like polyglycolide and polylactide are not produced in India, consumption of lactic acid is confined to food processing and the pro-... 

Cargill Dow LLC has developed a patented, low-cost continuous process for the production of lactic acid-based polymers. The process combines the substantial environmental and economic benefits of synthesizing both lactide and PLA in the melt rather than in solution and, for the first time, provides a commercially viable biodegradable commodity polymer made from renewable... 

In collaboration with Purdue University, we demonstrated (20) that nano alumina substrates can serve as scaffolding for the growth of osteoblast (human bone) cells. The study was aimed at developing bone growth cements. The nano alumina, blended into biodegradable (e.g.-lactic acid based) polymers were found to facilitate the proliferation of such cells. There was no toxic affect on osteoblast cells, and by inference nano alitmina would have no affect on other mammalian cells. 

Zhang J.F., Sun X., Poly(lactic acid)based bioplastics, in Biodegradable polymers for industrial applications, Ed. Smith R., CRC, 2005, Woodhead Publishing Limited, Cambridge -England, 2005, pp. 251-288, Chapter 10. 

Fig.9 Block copolymer based on an L-lysine dendron, a biodegradable L-lactic acid polymer chain and a cholesterol unit...

Most synthetic polymers are not biodegradable. However, there are a few synthetic polymers which are truly biodegradable. Some are water-soluble and become biodegradable once dissolved. Others are insoluble in water. The major families are lactic acid-based polymers, polycapro-lactone, other synthetic polyesters, and polyvinyl alcohol. 

Gattin R., Copinet A., Bertrand C., Couturier Y Comparative biodegradation study of starch- and poly lactic acid-based films, J. Polym. Environm. 9 (2001) 11. 

Although some microbial enzymes can degrade lactic acid-based polymers and stereocopolymers in vitro [18], biodegradation in vivo was soon excluded because humans do not possess enzymes capable of degrading high molar mass lactic acid polymers [19]. 

Lactic acid is commercially used in food, beverages and industrial applications, as well as in pharmaceuticals and personal care products. It is also the monomeric precursor for polylactic acid (PLA). Market growth in the industrial applications segment is expected to result primarily from lactic acid-based biodegradable polymers for food and nonfood packaging, bottles and fibre applications, and lactate esters [16]. 

Petinakis, E., Liu, X., Yu, L., Way, C., Sangwan, P., Dean, K., et al., 2010. Biodegradation and thermal decomposition of poly (lactic acid)-based materials reinforced by hydrophilic fillers. Polym. Degrad. Stabil. 95, 1704-1707. 

Lactic acid based polymer such as PLA belongs to the family of ahphatic polyesters. The PLA is formed by polycondensation of lactic acid (2-hydroxy propionic acid). It is a biodegradable polymer with a reasonable shelf life, for a wide variety of consumer products, such as paper coatings, films, moulded articles, and fiber applications (Datta et al., 1995). It degrades slowly by simple Itydrolysis of the ester bond to convert into harmless, natnral products like CO and H O (Drumright et al., 2000). 

Zhang, J-F., Sun, X. Poly(lactic acid)-Based Bioplastics, Biodegradeable Polymers for Industrial Applications. Smith, R. ed. CRC Press LLC, Boca Raton, FL, (2005)... 

The biodegradable polymer available in the market today in largest amounts is PEA. PEA is a melt-processible thermoplastic polymer based completely on renewable resources. The manufacture of PEA includes one fermentation step followed by several chemical transformations. The typical annually renewable raw material source is com starch, which is broken down to unrefined dextrose. This sugar is then subjected to a fermentative transformation to lactic acid (LA). Direct polycondensation of LA is possible, but usually LA is first chemically converted to lactide, a cyclic dimer of LA, via a PLA prepolymer. Finally, after purification, lactide is subjected to a ring-opening polymerization to yield PLA [13-17]. 

Early development of polymers in injectable drug delivery primarily involved PLA and poly(lactic-co-glycolic) acid (PLGA) due to the prior use of these polymers in biomedical applications as sutures. Besides the safe and biocompatible nature of these polymers, their ease of availability made them ideal first candidates for screening parenteral CR formulations. Some of the early biodegradable polymer-based products for injectable sustained release used these polymers. However because... 

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