Polylactic Acid

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monomer-lactic acid

biodegradable

Process

separate out starch and sugar in raw materials eg. corn, potatoes, wheat

starch and sugar in fermentation vat, high temperature α-amylase breaks starch down and glucoamylase breaks broken down starch into glucose

catalyst for reaction is lactic acid producing bacteria

two lactic acid molecules combine, eliminate water, and form one molecule, lactide

distillation purifies the cyclic lactic acid

through polymerization PLA forms

Progress

expensive to produce but fermentation process improved so less expensive

used for medical sutures, implants, controlled drug release, facial operations

now used as a plastic

Evaluation

used in medical operations as body absorbs it after time

used in horticulture industry for packaging over polystyrene as it is biodegradable

unknown reaction with pesticides

2000 olympic games plastic cutlery PLA, 26million kg of waste decomposed

now used for candy wrappers, chip packets, soft drink bottles

reduces landfill as it breaks down but produces methane, CO2, water

low flammability and smoke generation

PLA considered great possibility for future