Petroleum-based plastics Polypropylene

Despite its origin form the nature, PLA s good stiffness and strength has enabled it to compete with other existing chemically based commodity plastics. Previous study on the mechanical properties of neat PLA by Jacobsen et al. [1] showed that PLA has great potential to be a substitute polymer for petroleum based plastics. The respective values of mechanical properties of PLA [2] with comparison of other petroleum based plastics e.g. polypropylene (PP) [3], polystyrene (PS) [4], high density polyethylene (HOPE) [5], polyamide (PA6) [6] shown in Fig. 11.2. 

Generally speaking, bio-based plastics include starch-based plastics, protein (soybean protein) based plastics, and cellulose-blended plastics. They can also be blended with conventional plastics such as polyethylene (PE), polypropylene (PP), and poly(vinyl alcohol). However, such bio-based plastics are only partially biodegradable. The residual petroleum-based plastics remain as broken pieces, creating additional pollution. In addition, these plastics have intrinsic thermal and mechanical weaknesses, and they are now discouraged for applications. 

Starch-based plastics can be classified as compostable if the additives are also biodegradable under industrial compost environment conditions. Starch can be an additive for petroleum-based plastics like polyethylene, polypropylene, polyurethane, and polyester. However, these starch-filled petroleum-based plastics are not included in this book since they would not biodegrade under industrial composting conditions and would not be recyclable with commercial mechanical recycling operations. 

Thus, PHAs can be a key player in the bioplastic market however, to achieve this, production of PHAs must be made more cost effective, so that its price is comparable or cheaper than petroleum-based plastics. The cost for PHA production has been reduced from US 16 per kilogram to US 2 (approx. 1.55 or 1.35) per kilogram. Metabolix in partnership with Archer Daniels Midland in 2009 started to market PHAs under the trade name Mirel at US 1.02 per kilogram of Mirel pellets. " Therefore, though efforts have been made in reducing the cost of PHA production, it is still three times more expensive than polypropylene, as shown in... 

In 2002, the world production of polymers (not including synthetic libers and rubbers) was ca. 190 million metric tons. Of these, the combined production of poly(ethylene terephthalate), low- and high-density polyethyelene, polypropylene, poly(vinyl chloride), polystyrene, and polyurethane was 152.3 milhon metric tons [1]. These synthetic, petroleum-based polymers are used, inter alia, as engineering plastics, for packing, in the construction-, car-, truck- and food-industry. They are chemically very stable, and can be processed by injection molding, and by extrusion from the melt in a variety of forms. These attractive features, however, are associated with two main problems ... 

H., and Harrison, S.T.L. (2007) Environmental analysis of plastic production processes comparing petroleum-based polypropylene and polyethylene with biologically-based poly-P-hydroxybutyric add using life cyde analysis./. Biotechnol, 130 (1), 57-66. 

Recently, the possibility of replacing petroleum-derived synthetic polymers with natural, abundant and low-cost biodegradable products has gained much interest in both academic and industrial fields. " For instance, the production of plastics in Europe reached 57 million tons in 2012, mostly divided between polyethylene, polypropylene, poly(vinyl chloride), polystyrene and poly(ethylene terephthalate) production. These fossil-based plastics were consumed and discarded into the environment, generating 10.4 million tons of plastic waste, most of which ended up in landfills (Figure 1). 

Mechanical Properties of Petroleum-based Polypropylene Injection Molding Grade Plastics... 

Tile is based mainly on vinyl chloride and vinyl acetate copolymers. Some polypropylene tile systems have recendy been iatroduced. A petroleum resia is usually employed as an extender and processiag aid conventional vinyl plasticizers and stabilizers also are iacorporated. Reinforcing fibers and limestone constitute the remainder of the tile composition the fibers contribute hot strength for processiag and dimensional stabiHty ia the finished tile, limestone suppHes bulk at an economical cost. Stable pigments are also iacorporated. Siace tile is iastalled oa and below grade level, it is important that the finished product be resistant to the effects of moisture and alkaH. 

After 1950, the rapid growth of petroleum and methane based production of plastics and synthetic fibres became the most prominent feature of the Italian chemical industry/ Montedison, created in 1966 through a merger between the electrical company Edison and Montecatini, in that year produced between 50 and 100 per cent of Italy s aromatics, polyethylene, polypropylene, acrylic fibres, PVC and polyesters." Such a remarkable performance may appear surprising, considering that up to 1950 Montecatini s experience in polymerization had been mainly confined to the more traditional phenol plastics (Bakelite, etc.) and urea-formaldehyde resins (Caurit, etc.). The production of polyvinyl resins and the polyamide fibre nylon had been experimental rather than continuous." The most advanced polymerization procedures... 

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