Biodegradable polymers polylactic acid

Meanwhile, Fujitsu and Toray Industries have developed the first large-scale notebook computer housing based on polylactic acid biodegradable polymers. The housing is moulded of a specially developed PLA/polycarbonate blend that provide the required heat and flame resistance. 

Table 6.1 shows global consumption of polylactic acid biodegradable polymers by major world region for the years 2000, 2005 and 2010. 

World consumption of polylactic acid biodegradable polymers has increased significantly over the last five years as major suppliers such as Nature Works have brought their 140,000 tonnes per annum plant fully on stream. In 2005, world consumption of PLA amounted to 35,800 tonnes against 8,700 tonnes five years earlier. During the period 2005-2010, PLA consumption is forecast to reach 89,500 tonnes, which represents a compound annual growth rate of 20.1%. 

ComCard International manufactures a degradable polylactic acid-based polymer called Mazin. It also contains a proprietary additive polymer. The lactic acid is derived from corn. The polymer has been tested at the University of Nebraska to verify its biodegradability. ... 

Polylactates are an interesting class of biodegradable polymers which may be made from either renewable or petroleum feedstocks. The synthesis of lactic acid raises real issues concerning the relative greenness of the renewable and non-renewable (HCN) route as discussed in Chapter 2. A summary comparison of the greenness of both routes is shown is Table 6.4. Without a full LCA the choice of route on environmental grounds is not easy and at least partly depends on plant location and raw material availability. 

Polylactic acid (PLA) has been produced for many years as a high-value material for use in medical applications such as dissolvable stitches and controlled release devices, because of the high production costs. The very low toxicity and biodegradability within the body made PLA the polymer of choice for such applications. In theory PLA should be relatively simple to produce by simple condensation polymerization of lactic acid. Unfortunately, in practice, a competing depolymerization process takes place to produce the cyclic lactide (Scheme 6.10). As the degree of polymerization increases the rate slows down until the rates of depolymerization and polymerization are the same. This equilibrium is achieved before commercially useful molecular weights of PLA have been formed. 

The use of biodegradable polymers, especially polylactic acid (PLA), in oral solid dosage forms has been reported in the literature. PLA has been used as a matrix for phenobarbital tablets (9). Similarly, the use of polylactide as a matrix for oral dosage form of naproxen has also been reported (10). 

It polymerises to form the polymer, polylactic acid (PLA) which is biodegradable, a Suggest two advantages that PLA has compared with a polymer made from petroleum. [2]... 

DL-Polylactic acid, for the most part, was found to erode in about 12 months. Slow degradation of DL-polylactic acid often becomes a limitation on its use. This rate can be accelerated appreciably by copolymerizing with up to 50 mol% glycolide to yield complete erosion in as fast as 2 to 3 weeks. Incorporation of glycolide into the polylactide chain alters crystallinity, solubility, biodegradation rate, and water uptake of the polymer. 

In order to decrease human consumption of petroleum, chemists have investigated methods for producing polymers from renewable resources such as biomass. Nature Works polylactic acid (PLA) is a polymer of naturally occurring lactic acid (LA), and LA can be produced from the fermentation of corn. The goal is to eventually manufacture this polymer from waste biomass. Another advantage of PLA is that, unlike most synthetic polymers which litter the landscape and pack landfills, it is biodegradable. PLA can also be easily recycled by conversion back into LA. It can replace many petroleum-based polymers in products such as carpets, bags, cups, and textile fibers. 

Lactic acid has been used as a food preservative and food-flavoring compound. Recent attention on lactic acid has been for its use in making polylactic acid (PLA), a biodegradable polymer. As a result, the market for lactic acid is rapidly growing. Under batch fermentation conditions, homolactic fermentative... 

Naturally biodegradable polymers produced in nature are renewable. Some synthetic polymers are also renewable because they are made from renewable feedstock, for example polylactic acid is derived from agricultural feedstock. 

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. 

Starch-based materials represent the largest class of biodegradable polymer with 44,800 tonnes (including loose-fill foam packaging) consumed in 2005. Excluding loose-fill, starch-based materials amounted to 21,700 tonnes in 2005. Polylactic acid (PLA) is the second largest material class with 35,800 tonnes in 2005, followed by synthetic aliphatic-aromatic copolyesters with 14,000 tonnes. The embryonic PHA category amounts to around 250 tonnes. 

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