I. Polylactic acid PLA：
Polylactic acid (PLA) is a novel biodegradable material made from starch derived from renewable plant resources such as maize. With good biodegradability, it can be completely degraded by microorganisms in nature after use, and eventually generate carbon dioxide and water. It does not pollute the environment, which is very beneficial to the protection of the environment. It is recognized as environmentally friendly material. It is understood that PLA consumption accounted for 45.1% of biodegradable plastics, is worthy of the main force.
The degradation of POLylactic acid can be divided into two stages: 1) Pure chemical hydrolysis to lactic acid monomer; 2) Lactic acid monomer degrades into carbon dioxide and water after microbial action. The food cup made of PLA can be completely degraded in only 60 days, which truly achieves both ecological and economic effects.
2.Two, poly 3- hydroxyalkanoate PHA：
PHA is an aliphatic copolymer of polyesters with different structures synthesized by fermentation of various carbon sources by microorganisms. Among them, the most common are poly3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and copolymer of PHB and PHV (PHBV).
Main uses: disposable tableware, non-woven cloth, packaging materials, agricultural film, toys, film, plastic, fiber and other degradable products.
3.Three, poly ε -caprolactone PCL：
Polyε -caprolactone (PCL) is a low melting point polymer prepared by ring-opening polymerization of ε -caprolactone, and its melting point is only 62℃. Biodegradability of PCL has been studied since 1976. PCL can be completely decomposed by microorganisms in both anaerobic and aerobic environments.
Compared with PLA, PCL had better hydrophobicity, but the degradation rate was slower. At the same time, the synthesis process is simple and the cost is low. PCL has excellent processing performance and can be made into film and other products by ordinary plastic processing equipment.
