What: Biopol (polyhydroxyalkanoate - PHA) is technically is a co-polymers, consisting of the monomers - polyhydroxybutyric (PHB)and polyhydroxyvalerate (PHV)acids produced in nature from the fermentation of sugars by the bacteria, Azobacter and Psuedomonas. The significance of this is Biopol is that it is produced naturally by renewable agricultural resources, and most importantly, other natural bacteria can consume this polyester, so it is being promoted as fully biodegradable.
[FONT="]How Made: [/FONT][FONT="]The bacterium uses this polymer as a storage reservoir of carbon, which can amount to more than half of the dry weight of the organism. The polymer is produced industrially by bacteria (Alcaligenes Eutrophus), in tanks of carbon foods. It is then purified by dissolving in chlorinated hydrocarbon (trichloromethane), removing the solid waste by centrifuging and precipitating the PHB from solution and drying powder. Genetic engineering for the production of Biopol has been attempted for a viable and economical method (E-coli bacteria). <o>
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[FONT="]Properties:[/FONT][FONT="] The Biopol backbone contains a chiral center (always
R configuration). The regular stereochemistry allows the chains to pack efficiently, so Biopol is a tough, semicrystalline material. It is a stable polymer, resistant to water and hydrolytic degradation. Biopol has a good ultra-violet resistance. But has poor resistance to acids and bases. It us soluble in chloroform and other chlorinated hydrocarbons. It has a melting point of [/FONT][FONT="]175<sup>0</sup>C and glass transition temperature of 15<sup>0</sup>C. It has a tensile strength of 40 MPa which is close to that of polypropylene, however biopol sinks in water while polypropylene floats.
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[FONT="]Uses:[/FONT][FONT="] Biopol can be used for many packaging applications, for example packaging for products such as shampoos and cosmetics, rubbish bags. It is also used for disposable nappies, plastic plates and cups, golf tees, disposable razors, credit cards, composting bags, fishing nets, flower pots, and mulch mats. These uses for biopol are currently more expensive than the conventional alternative, however biopol has the advantage of being biodegradable and thud allowing better waste management.[/FONT]
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[FONT="]Potential Uses:[/FONT][FONT="] <o>></o>>[/FONT]
[FONT="]Medical uses[/FONT][FONT="] - [/FONT][FONT="]High grade Biopol is being made for medical applications, including woven patches for use inside the body to protect tissues from scarring after surgery. After the wound is healed, enzymes in the blood dissolve away the patch.
Other medical uses could come in the form of guazes, sutures (stitches), filaments, implants and drug carriers. Biopol is compatible within the body and hence rejection is not a problem within the body. <o>></o>>[/FONT]
[FONT="]Agricultural uses[/FONT][FONT="] - Slow release pesticides and fertilizers, mulches that degrade over time Pharmaceutical uses - Coatings for drugs, homopolymers can act as chiral substrates for drugs.
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