Question

What is PHBV? How is it useful to man?

Answer 1

Hint: PHBV stands for 3-hydroxybutyrate-co-3-hydroxyvalerate and is a type of polyhydroxyalkanoate polymer. It is a natural biodegradable plastic produced by bacteria and is used as an alternative to the synthetic polymers and is non-toxic in nature.

Complete answer:
3-hydroxybutyrate-co-3-hydroxyvalerate is a thermoplastic linear aliphatic polymer which is obtained by the copolymerization of 3-hydroxybutanoic acid and 3-hydroxypentanoic acid. It is produced naturally by many bacteria such as Paracoccus denitrificans and can also be produced by many genetically engineered plants. PHBV may also be prepared from butyrolactone and valerolactone in the presence of a catalyst named oligomeric aluminoxane. The monomers, 3-hydroxybutanoic acid and 3-hydroxypentanoic acid are connected by ester bonds which act as the backbone of the polymer and the polymer is made up of oxygen and carbon atoms. The property of the PHBV depends upon the ratio of these two monomers in it. 3-hydroxypentanoic acid provides flexibility while 3-hydroxybutanoic acid provides stiffness. Thus PHBV can be synthesized to resemble either polypropylene or polyethylene by changing the ratio of the involved monomers. If there is an increase in the ratio of 3-hydroxybutanoic acid to 3-hydroxypentanoic acid, there is an increase in melting point, water permeability, glass transition temperature (Tg) and tensile strength. However impact resistance is reduced and the substance can break on the application of huge stress. PHBV is a thermoplastic polymer and is brittle, has low elongation at break and small impact resistance.

Note:
PHBV has an application in the medical implants and repairs, controlled release of drugs, orthopedic devices, specialty packaging, and manufacturing bottles for consumer goods. It is also biodegradable and can be used as an alternative to non biodegradable plastics which can act as a savior to mother nature and as a perfect usable material for human consumption.