It is formed by polycondensation of succinic acid and 1, 4- butanediol, and the raw material source is petroleum or biological resource fermentation. PBS is easily decomposed into carbon dioxide and water by various microorganisms or enzymes in nature. Due to the limited raw materials of succinic acid in China, PBAT and PBSA, derivatives of PBS, came into being. Their properties are basically similar to those of PBS, but their processability is not as good as that of PBS.
Advantages and disadvantages: it has good biocompatibility and bioabsorbability, and good heat resistance.
Usage: PBS can be used in packaging films, tableware, foaming packaging materials, daily necessities bottles, medicine bottles, agricultural films, pesticide and fertilizer slow-release materials and other fields.
polylactic acid
The production of polylactic acid is based on lactic acid, and traditional lactic acid fermentation mostly uses starch as raw material. At present, the United States, France, Japan and other countries have developed and utilized corn, sugar cane, sugar beet, potato and other agricultural and sideline products as raw materials to produce lactic acid by fermentation, and then produce polylactic acid. The production process includes grinding corn into powder, separating starch, extracting original glucose from starch, converting glucose into lactic acid through a fermentation process similar to beer, and making the extracted lactic acid into the final polymer-polylactic acid.
Advantages and disadvantages: PLA has reliable biological safety, biodegradability, good mechanical properties and easy processing. The disadvantage is that the degradation conditions are relatively harsh, but PLA is in the forefront because of its relatively low cost in biodegradable plastics.
The degradation process of polylactic acid: firstly, it is pure chemical hydrolysis to lactic acid monomer; Lactic acid monomer is decomposed into carbon dioxide and water under the action of microorganisms. The food cup made of polylactic acid can be completely degraded in just 60 days, which truly achieves the dual effects of ecology and economy.
Uses: Widely used in packaging, textile industry, agricultural plastic film and biomedical polymer industry.
Polyester (PBAT)
PBAT is a kind of thermoplastic degradable plastic, which is generally produced by petrochemical or biological fermentation with fatty acids and butanediol as raw materials. PBAT is widely used in disposable packaging film and agricultural film field because of its good film forming and easy film blowing. In addition, PBAT has excellent biodegradability and is one of the most active biodegradable materials in the research of degradable plastics and the best market application.
Advantages and disadvantages: PBAT has good ductility, elongation at break and impact property. But one of the fatal weaknesses is poor heat resistance.
Uses: It can be used in packaging, tableware, cosmetic bottles and medicine bottles, disposable medical supplies, agricultural films, pesticide and fertilizer slow-release materials, biomedical polymer materials and other fields.
Polyhydroxyalkanoate
Polyhydroxy fatty acid esters are aliphatic polyesters with different structures synthesized by microorganisms through fermentation of various carbon sources, among which poly -3- hydroxybutyrate (PHB), poly-hydroxyvalerate (PHV) and poly -PHB and PHV * *(PHBV) are the most common.
Degradation process of PHA: PHA can be completely degraded into β -hydroxybutyric acid, carbon dioxide and water in organisms after use.
Advantages and disadvantages: PHAs degradable plastics have high thermal deformation temperature and good biocompatibility, but have narrow processing temperature range, poor thermal stability, high brittleness and unstable production quality.
Uses: It can be used for disposable articles, surgical gowns for medical devices, packaging bags and compost bags, medical sutures, repair instruments, bandages, orthopedic needles, anti-adhesion membranes and stents.