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J Polym Environ (2013) 21:738759 DOI 10.1007/s10924-013-0577-z
ORIGINAL PAPER
PLA and Montmorilonite Nanocomposites: Properties, Biodegradation and Potential Toxicity
Patrcia Moraes Sinohara Souza
Ana Rita Morales Maria Aparecida Marin-Morales
Lucia Helena Innocentini Mei
Published online: 5 May 2013 Springer Science+Business Media New York 2013
Abstract The concern related to solid waste increases efforts to develop products based on biodegradable materials. At present, PLA has one of the highest potentials among biopolyesters, particularly for packaging. However, its application is limited in some elds. In order to optimize PLA properties, organo-modied montmorilonites have been extensively used to obtain nanocomposites. Although PLA nanocomposites studies are widely reported in the literature, there is still few information about the inuence of organoclays on de biodegradation process, which is a relevant information, since one of the main purposals related to the nal disposal of biopolymers as PLA is composting. Besides, in the last years some research has been conducted in order to evaluate the potential toxicity of montmorilonite, unmodied or organo-modied. Since the use of montmorilonite is expanding in different applications, human exposure and risk assessment are important issues to be investigated. In this context, this review intends to compile available information related to common organoclays used for PLA nanocomposites, its properties, biodegradation analysis and potential toxicity evaluation of nanocomposites, focused on montmorilonite as ller. Two issues of relevance were pointed out. The rst is food safety and quality, and the second consideration is the environmental effect.
Keywords PLA Organoclays Nanocomposites
Biodegradation Toxicity
PLA
PLA or poly (lactic-acid) was discovered in 1932 by Car-others (at DuPont). He was only able to produce a low molecular weight PLA by heating lactic acid under vacuum while removing condensed water. PLA was rst used in a blend with polyglycolic acid, as suture material and sold under the name Vicryl in the USA in 1974 [1].
Lactic acid has two optical isomers (L-lactic acid and
D-lactic acid). Chemical synthesis of lactic acid is mainly based on the hydrolysis of lactonitrile by strong acids, which provides only the racemic mixture of D-lactic acid and
L-lactic acid. The interest in the fermentative production of lactic acid has increased due to the prospects of environmental friendliness and the use of renewable resources instead of petrochemicals. Besides, fermentation allows obtaining...