Biodegradable and Non-biodegradable Polymers Preparation and Properties
→ Bio-polymers : Many polymers which are present in plants and animals such as polysaecharides (starch. cellulose), proteins and nucleic acids etc. which control various life processes in plants and animals are called biopolymers. Examples are proteins, Carbohydrates, Nucleic acids, Lipids etc.
→ Biodegradable Polymers : These can be natural or synthetic both. These are degraded to small molecules by bacteria. Examples are PHBV, Nylon 2,6 etc.
→ Non-biodegradable Polymers : These are synthetic polymers and cannot be biodegraded. Examples are polythene, bakelite, teflon, PVC, terviene etc, Non-biodegradable polymers are very useful in daily life.
→ As these are non-biodegradable, their disposal is a big problem. Management of polymer waste is a very serious problem. Therefore, such polymers are synthesised which can be degraded. Some of them are:
→ Polylactic Acid (PLA) : It is an aliphatic polyester. It is obtained by polymerisation of the dimer of lactic acid (HO—CH(CH3) COOH) or by micro biological syithesis of lactic acid followed by the polycondensation and removal of water by evaporation.
→ Use : Mainly it is used in me4icine for making stitches, dialysis etc. It is also used in preparation of bio.plastic.
→ Polycaprolactone (PCL) : It is a low melting point polyester and is obtained by chain polymerization of the lactone of 6-hydroxy hexanoic acid.
→ Use : It is used in Control Drug Release for making capsules. These capsules when enters in human body then ester chain of PCL is degraded and drugs is released slowly in the body.
→ PGA (Polyglycolic Acid) : It is a linear aliphatic polyester. It is obtained by the chain polymerization of dimer of glycolic acid, H O—CH2COOH.
→ Uses : PGA are very strong fibres and are soluble in water mainly they are used in stiching wounds.
→ PHBV (Poly-β-Hydroxybutyrate-Co-β-Hydroxy Valerate) : PHBV is a copolymer of 3.hydroxy hutanoic acid, and (3.Hydroxypentanoic Acid), in which, the monomer units are connected by ester linkages.
→ Nylon-2-Nylon-6 : It is an alternating polyamide copolymer of glycine (H2N—CH2—COOH) and Amino caproic acid [H2N(CH2)5COOH] and is biodegradable.