Polylactic Acid for Bioplastic
Polylactic acid (PLA) is a transparent plastic made from natural resources. It not only resembles conventional petrochemical mass plastics (like PE or PP) in its characteristics, but it can also be processed easily on standard equipment that already exists for the production of conventional plastics. PLA and PLA-Blends generally come in the form of granulates with various properties and are used in the plastic processing industry for the production of foil, moulds, tins, cups, bottles and other packaging. Fold and twist retention for PLA is comparable to cellophane and almost 50% higher than polypropylene. Bottles made from PLA can show characteristics similar to PET. But PLA’s carbon dioxide (CO2) transfer rate is high so it cannot retain carbonation found in soft drinks or beer. Cargill Dow says that bottles made with PLA are best suited for dairy, juices or water products.
PLA contributes not only to decreasing oil consumption but also to the prevention of global warming because it originates from plants which absorb carbon dioxide in the atmosphere, therefore, the receipt and payment account of carbon dioxide breaks even. Meanwhile, conventional plastics, if incinerated, only increase carbon dioxide because they originate from fossil fuel.
PLA’s handicap is its low glass-transition temperature (Tg).
Poly(lactic acid) has become a significant commercial polymer. Its clarity makes it useful for recyclable and biodegradable packaging, such as bottles, yogurt cups, and candy wrappers. It has also been used for food service ware, lawn and food waste bags, coatings for paper and cardboard, and fibers-for clothing, carpets, sheets and towels, and wall coverings. In biomedical applications, it is used for sutures, prosthetic materials, and materials for drug delivery.