Polylactic acid properties

PLA is a chiral polymer containing asymmetric carbon atoms with a helical conformation. Polymers that have stereo centers in the repeating unit can exhibit two structures of maximum order, that 

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Al-Mulla, E.A.J., Yimus, W.MZ., Ibrahim, N.A. and Abdul Rahman MZ. 2010b. Properties of epoxidized palm oil plasticized polylactic acid. Journal of Materisls Science 45 ... 

Polymer blends have been categorized as (1) compatible, exhibiting only a single Tg, (2) mechanically compatible, exhibiting the Tg values of each component but with superior mechanical properties, and (3) incompatible, exhibiting the unenhanced properties of phase-separated materials (8). Based on the mechanical properties, it has been suggested that PCL-cellulose acetate butyrate blends are compatible (8). Dynamic mechanical measurements of the Tg of PCL-polylactic acid blends indicate that the compatability may depend on the ratios employed (65). Both of these blends have been used to control the permeability of delivery systems (vide infra). 

Polylactic acid (PLA) reinforced with kenaf fibres developed by NEC for personal computer housings. With a 20% level of kenaf fibres, the main properties compete with glass fibre reinforced ABS but the cost is 50% higher. The flexural modulus is more than 4.5 GPa and the HDT reaches 120°C. 

Lactic acid is an important chemical that has wide applications in food, pharmaceutical, cosmetic, and chemical industries. There are increasing interests in production of lactate esters and biodegradable polylactic acid (PLA) from lactic acid. Lactate esters are a relatively new family of solvents with specific properties. They are considered safe and are biodegradable (1). In many situations they can replace toxic solvents. Their functions vary from that of intermediates in chemical reactions to solvents in ink formulations and cleaning applications (2). PLA has been widely used in medical implants, sutures, and drug-delivery systems because of its capacity to dissolve over time (3-5). PLA also can be used in products such as plant pots, disposable diapers, and textile fabrics. 

Polylactic acid (PLA) is a biodegradable polymer derived from lactic acid. It is a highly versatile material and is made from 100% renewable resources like corn, sugar beet, wheat and other starch-rich products. Polylactic acid exhibits many properties that are equivalent to or better than many petroleum-based plastics, which makes it suitable for a variety of applications. 

In 2005, Japanese company Kaneka developed the first beads-process, foamed resin moulded product, which is based on polylactic acid. The new KanePearl product has the strength and shock-absorbing properties of existing beads-process, foamed polystyrene products. 

Japanese company NEC has developed a plant-derived bioplastic whose main component is polylactic acid. It is said to possess the world s best flame retardance for a product of this type. This has been achieved without the use of halogenated or phosphorous flame retardants. NEC has applied proprietary property-modifying additives such as inorganic heat absorbants, high flow modifiers and impact modifiers to realise the bioplastic. The material conforms to the UL94 5V standard, which means it can be utilised in a wide variety of electronic products, including personal computer housing. 

In June 2004, Treofan introduced its new biodegradable and compostable Biophan film made from polylactic acid supplied by NatureWorks LLC. According to the company, Biophan offers exceptional transparency and gloss, the ability to transmit water vapour, and outstanding sealing properties. Biophan is also printable, resistant to oil, fat and alcohol, and is thermoformable. Biophan disintegrates completely into water and carbon dioxide within 45 days. 

In recognition of the superior properties and the huge potential market of polylactic acid, Cargill Inc. and The Dow Chemical Company started a joint venture Cargill Dow LLC to produce lactic acid using... 

Hunt, J. Large-scale production, properties and commercial applications of polylactic acid polymers. Polym. Degrad. Stab. 1998, 59 (1-3), 145-152. 

L. Averous, "Polylactic acid synthesis, properties and applications," in B.N.a.G. A. eds.. Monomers, Polymers and Composites from Renewable Resources, Elsevier Limited Publication, pp. 433,2008. 

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