Poly lactic acid -based Polymers

Poly(lactic acid)-based polymers or polylactides (PLAs) are biopolyesters derived from lactic acid, which is generally produced by the fermentation of com 

Polyethylene (PE) is a thermoplastic commodity made by the chemical industry through the addition polymerization of ethene and which heavily used in a variety of consumer products. PE is classified into several different categories, based mostly on its density and branching. The mechanical properties of PE depend significantly on variables such as the extent and type of branching, the crystal structure and the molecular weight. The following are types of PE  

Reference Substrates Experimental conditions Main results 

Extruded starch acetate foams PLA with pre-conditioned yard waste. Extruded foams of high amylose starch used as control. 

Simulated composting conditions according to ASTM and ISO standards. 

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Tsuneizumi et al. [13] studied the chemical recycling of poly(lactic acid)-based polymer blends using environmentally benign catalysts, clay catalysts, and enzymes. Poly(L-lactic acid) (PLLA)-based polymer blends (e.g., PLLA/polyethylene [PE] and PLLA/poly(butylenes succinate) [PBS]) were degraded into repolymerizable oligomer. 

Mohamed, A., Finkenstadt, V.L., Rayas-Duarte, P. et al. (2009) Thermal properties of extruded and injection-molded poly(lactic acid)-based cuphea and lesquerella bio-composites. Journal of Applied Polymer Science, 111, 114-124. 

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. 

Y. Altun, M. Dogan, and E. Bayramli, Effect of alkaline treatment and pre-impregnation on mechanical and water absorbtion properties of pine wood flour containing poly (lactic acid) based green-composites. 7 Polym. Environ. 21(3), 850-856 (2013). 

The low heat deflection temperature of PLA limits its use for several application fields, such as in packaging materials and electronic components. The introduction of rigid building blocks [63] or cross-links [64] is known, for instance, to increase the glass transition temperature and/or heat resistance of lactic acid based polymers. The effect of different amounts of comonomers in the prepolymers on the Tg and mechanical properties of poly(ester-urethane)s is demonstrated in Table 3.2. The heat resistance of poly(ester-ure-thane)s can be improved by the copolymerization of lactic acid with D,L-mandehc acid. This broadening of the operating temperature range is of clear practical importance. The incorporation of other comonomers that impede rotation and make polymer chains less mobile also causes an increase in Tg, even if the same comonomers can depress the rate of poly condensation [50]. 

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. 

The ecotoxicological impact of lactic acid-based polymers was evaluated by biotests, i.e. by the Flash test, measuring the inhibition of light production of Vibrio fisheri, and by plant growth tests with cress, radish, and barley [16]. Poly(lactic acid)s, poly(esterurethane)s... 

Lee SY, Xu YX, Hanna MA (2007) Tapioca starch-poly (lactic acid)-based nanocomposite foams as affected by type of nanoclay. Int Polym Process 22(5) 429-435 Lee B-H, Kim H-S, Lee S, Kim H-J, Dorgan JR (2009) Bio-composites of kenaf fibers in polylactide role of improved interfacial adhesion in the carding process. Compos Sci Technol 69 2573-2579... 

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. 

Gu, C.-H., Wang, J.-L, Yu, Y., Sun, H., Shuai, N., Wei, B. Biodegradable multilayer barrier films based on alginate/polyethyleneimine and biaxially oriented poly(lactic acid). Carbohydr. Polym. 92, 1579-1585 (2013)... 

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)... 

Based on these studies, it is obvious that poly(N-acylhydroxy-proline esters) are very slowly degrading polymers. These materials may therefore be useful for long-term applications, such as implantable, multiyear contraceptive formulations. For such applications the degradation rates of poly (lactic acid)/poly (glycolic acid) devices would probably be too rapid. 

Watanabe J, Eriguchi T, Ishihara K (2002) Cell adhesion and morphology in porous scaffold based on enantiomeric poly(lactic acid) graft-type phospholipid polymers. Biomacromolecules 3 1375-1383... 

In the current industrial process, nisin is manufactured by fermentation of L. lactis subsp. lactis in a milk-based medium. Biosynthesis of nisin is coupled with the growth of lactic acid bacteria and the production of a significant amount of lactic acid (7). Lactic acid is an important chemical for food processing. It can also be used as a raw material in the production of the biodegradable polymer poly(lactic) acid (12). Unfortunately, lactic acid is not recovered in the current nisin process. 

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