Biodegradable Plastics
Polylactide (PLA) is a bioplastic basically made from starch, the basic building material. Here lactic acid (CH3CHOHCOOH) is produced through fermentation where microorganisms convert sugar feedstock into lactic acid. The lactic acid thus isolated is depolymerized to lactide and by Ring-opening polymerization with catalysts it is converted into Polylactide polymer of high molecular weight. Based on the particle size, the rate of biodegradability and transparency varies. They find use in soluble fibers, compose bags and renewable products.
Polyhydroxyalkanoates (PHA) polymers are produced naturally by microorganisms directly from sugar feedstock. The polymer is isolated, purified and processed. These components can be controlled by varying the ratio of sugar feedstock. Synthesized PHA is copolyester composed of 3-hydroxy fatty acids hydroxybuterate, hydroxyvalerate and hydroxyhexanoate. In all PHAs the hydroxyl substituted carbon atom is steriochemical -R configuration. Since they are composed of short chain and long chain length R groups, they are used for a variety of commercial applications.
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