Polyhydroxyalkanoate BIOPOL

Polyhydroxyalkanoates (PHAs) are also biodegradable polymers. These are condensation polymers of 3-hydroxycarboxyhc acids. Thus, like PLA, they are polyesters. The most common PHA is PHB, a polymer of 3-hydroxybutyric acid it can be used for many of the things that polypropylene is now used for. Unlike polypropylene that floats, PHB sinks. PHBV, a PHA marketed under the trade name Biopol, is a copolymer of 3-hydroxybutyric acid and 3-hydrox5rvaleric acid. It is being used for such things as wastepaper baskets, toothbrush holders, and soap dispensers. PHAs are degraded by bacteria to CO2 and H2O. 

The polyhydroxyalkanoates represents a range of polyesters produced from renewable resources by bacterial fermentation. The class includes the 3-hydroxybutyrate-co-3-hydroxyvalerate polymers marketed under the Biopol trademark. 

In particular, this chapter will concentrate on the physical properties of the first polyhydroxyalkanoates to be commercially exploited, the Biopol resins, launched by ZENECA Bio Products, Billingham, UK. These materials are copolymers of 3-hydroxybutyric acid (3HB) and 3-hydroxy valeric acid (3H V) ... 

Microbial polymers (e.g. poly(3)-hydroxybutyrate-hydroxyvalerate) are excreted or stored by micro organisms cultivated on starch hydrolysates or lipidic mediums. Isolation and purification costs could be high for those products that are obtained Ifom complex mixtures. Monsanto stopped the commercialisation of its product Biopol in 1999. Since then, production has been low but some new producers are entering the market (e.g. Coopeazucar in Brazil which has built new facilities for a pilot plant production of these polyhydroxyalkanoates). 

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