Acido polilactico

LAPoly-Lactic Acid: Production, Applications, Nanocomposites, and Release Studies
Majid Jamshidian, Elmira Arab Tehrany, Muhammad Imran, Muriel Jacquot, and St´phane Desobry e Abstract: Environmental, economic, and safety challenges have provoked packaging scientists and producers to partially substitute petrochemical-based polymers with biodegradable ones. The general purpose of this review isto introduce poly-lactic acid (PLA), a compostable, biodegradable thermoplastic made from renewable sources. PLA properties and modifications via different methods, like using modifiers, blending, copolymerizing, and physical treatments, are mentioned; these are rarely discussed together in other reviews. Industrial processing methods for producing different PLA films, wrappings, laminates,containers (bottles and cups), are presented. The capabilities of PLA for being a strong active packaging material in different areas requiring antimicrobial and antioxidant characteristics are discussed. Consequently, applications of nanomaterials in combination with PLA structures for creating new PLA nanocomposites with greater abilities are also covered. These approaches may modify PLA weaknesses forsome food packaging applications. Nanotechnology approaches are being broadened in food science, especially in packaging material science with high performances and low concentrations and prices, so this category of nano-research is estimated to be revolutionary in food packaging science in the near future. The linkage of a 100% bio-originated material and nanomaterials opens new windows forbecoming independent, primarily, of petrochemical-based polymers and, secondarily, for answering environmental and health concerns will undoubtedly be growing with time.

Mechanical recycling (segregated plastics, mixed plastics), biological recycling (sewage, compost, soil), and energy recovery (incineration, pyrolysis) are 3 alternative ways for plastics waste management, with each having someadvantages and disadvantages as to economical, processing, and technological aspects (Scott 2000). The above-mentioned concerns are negligible for biopolymers concerning the biodegradation process that takes place in nature. Biodegradation is defined as the degradation of a polymer in natural environments that includes changes in chemical structure, loss of mechanical and structural properties, andfinally, changing into other compounds like water, carbon dioxide, minerals, and intermediate products like biomass and humic materials. The natural environments contain chemical, biological, and physical forces with impinging factors like temperature, humidity, pH, O2 presence, and so on, which determine the rate and products of the biodegradation process (Zee 2005). Biopolymers are produced fromnatural resources and crude oil. Four categories of biopolymers are recognized: (a) extracted directly from natural raw materials, such as polysaccharides like starch and cellulose; proteins like gelatin, casein, and silk; and marine prokaryotes; (b) produced by chemical synthesis from bio-derived monomers such as poly-lactic acid (PLA), also known as poly(lactic acid) in the literature; (c) produced bymicroorganisms or genet´ MS 20100340 Submitted 3/29/2010, Accepted 6/10/2010. Authors are with Ecole ically modified bacteria such as polyhydroxyalkanoates (PHA), nationale sup´rieure d’agronomie et des industries alimentaires, Institut National Polye technique de Lorraine, 2 avenue de la Forˆt de Haye, 54501 Vandoeuvre, France. Direct polyhydroxybutyrate (PHB), hydroxyl-valerate (PHV), bacteriale cellulose, xanthan, and pullan; and (d) produced from crude oil like inquiries to author Jamshidian (E-mail: majid.jamshidian@ensaia.inpl-nancy.fr). aliphatic and aromatic polyesters, polyvinyl alcohol, and modified Today, polymers and materials used for food packaging consist of a variety of petrochemical-based polymers, metals, glass, paper, and board, or combinations hereof. The durability...