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BIOPLASTICS: BIOBASED PLASTICS AS RENEWABLEAND/OR BIODEGRADABLE ALTERNATIVES TOPETROPLASTICS1. Introduction‘‘Plastics’’ were introduced approximately 100 years ago, and today are one of themost used and most versatile materials. Yet society is fundamentally ambivalenttoward plastics, due to their environmental implications, so interest in bioplasticshas sparked.According to the petrochemical market information provider ICIS, ‘‘Theemergence of bio-feedstocks and bio-based commodity polymers production, intandem with increasing oil prices, rising consumer consciousness and improvingeconomics, has ushered in a new and exciting era of bioplastics commercialization.However, factors such as economic viability, product quality and scale of operationwill still play important roles in determining a bioplastic’s place on the commer-cialization spectrum’’ (1).The annual production of synthetic polymers (‘‘plastics’’), most of which arederived from petrochemicals, exceeds 300 million tons (2), having replacedtraditional materials such as wood, stone, horn, ceramics, glass, leather, steel,concrete, and others. They are multitalented, durable, cost effective, easy toprocess, impervious to water, and have enabled applications that were notpossible before the materials’ availability.Plastics, which consist of polymers and additives, are defined by their set ofproperties such as hardness, density, thermal insulation, electrical isolation, andprimarily their resistance to heat, organic solvents, oxidation, and microorgan-isms. There are hundreds of different plastics; even within one type, variousgrades exist (eg, low viscosity polypropylene (PP) for injection molding, highviscosity PP for extrusion, and mineral-filled grades).Applications for polymeric materials are virtually endless; they are used asconstruction and building material, for packaging, appliances, toys, and furniture,in cars, as colloids in paints, and in medical applications, to name but a few.Plastics can be shaped into films, fibers, tubes, plates, and objects such as bottlesor boxes. They are sometimes the best available technology. Many plastic productsare intended for a short-term use, and others have long-term applications (eg,plastic pipes, which are designed for lifetimes in excess of 100 yr).On the other hand, there is a growing debate about crude oil depletion andprice volatility, and environmental concerns with plastics are becoming moreserious. Approximately half of all synthetic polymers end up in short-livedproducts, which are partly thermally recycled (burnt), but to some extent endup on landfills or, worse, in the oceans, where large plastic objects are washedashore, sink or float (eg, the ‘‘North Pacific Garbage Patch,’’ which has continentaldimensions), and get fragmented to ‘‘microplastics’’ (particles between a fewmmand<5 mm) that harm and kill various organisms, finally ending up on our plates.It is estimated that globally some 900 billion plastic bags (shopping bags, wastebags, etc) are produced each year, with a typical average useful life of only a fewminutes and a significant fraction of them ending up as litter in the environment(3), having wasted energy, spoiling the scene, and seriously harming wildlife.1Kirk-Othmer Encyclopedia of Chemical Technology.
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