Biodegradable plastics refer to those that exist in nature under natural conditions such as soil and/or sand, and/or specific conditions such as composting conditions or anaerobic digestion conditions or in aqueous culture fluids Microorganisms such as bacteria, mold, and seaweed cause degradation, and eventually completely degrade into carbon dioxide (CO2) or/and methane (CH4), water (H2O) and mineralized inorganic salts of the elements and new biomass plastic. Among many biological materials, poly 3-hydroxyalkanoate (PHA), polylactic acid (PLA), polyε-caprolactone (PCL) and polybutylene succinate (PBS) are currently relatively mature in technology. The scale of industrialization is relatively large, and it is also the main species currently consumed in the market.
Biodegradable Trash Bag
Brief introduction of the main varieties of biodegradable trash bags
It is an aliphatic copolyester of different structures synthesized by microorganisms through fermentation of various carbon sources;
Poly 3-hydroxybutyrate (PHB), polyhydroxy valerate (PHV) and copolymers of PHB and PHV (PHBV);
The physical properties and mechanical properties are close to polypropylene plastics with high strength, high modulus, and good heat resistance;
It can be completely degraded into β-hydroxybutyric acid, carbon dioxide and water in the body;
Drug release systems, implants, and some devices that harmlessly decompose in the human body after healing.
It is a polyester chemically synthesized with microbial fermentation product-lactic acid as a monomer;
Different stereoregular products such as L-PLA, D-PLA, and DL-PLA;
Good moisture resistance, grease resistance, and airtightness, stable performance at room temperature, good modulus, and gloss;
When the temperature is higher than 55 ℃ or enriched with oxygen and microorganisms, it will automatically degrade to generate carbon dioxide and water;
General plastic fields such as films, lunch boxes, cups, etc.
The low melting polymer obtained by ring-opening polymerization of ε-caprolactone
PCL has good compatibility with synthetic plastics, rubber, cellulose, and starch, and materials with excellent properties can be obtained through blending and copolymerization
Compared with PLA, PCL has better hydrophobicity
In anaerobic and aerobic environments, PCL can be completely decomposed by microorganisms, but the degradation rate is slow
Excellent processing performance, made into films and other products
It uses aliphatic succinic acid and butanediol as raw materials, has petrochemical routes, and can also be produced by biological fermentation;
Excellent mechanical properties, good heat resistance, best processing performance, can be blended with a large number of fillers such as calcium carbonate and starch, low cost; general modulus and gloss;
Degradation occurs only when composting and other microorganisms are in contact, and the degradation rate, especially the disintegration rate, is slightly worse;
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, etc .;
In terms of raw material sources, biodegradable plastics can come from renewable materials (such as biomass materials, referring to natural polymer materials grown in nature, mainly including plant fibers, starch, cellulose, protein, lignin and chitosan Category, etc.), and can also come from fossil resources (such as oil, natural gas, coal, etc.). If the material is derived from both renewable materials and has biodegradability (as shown in the figure below PLA and bio-based PBS), it is in line with the concept of renewable, recycled environmental protection, energy-saving, and emission reduction.
Biodegradable plastics can reduce carbon dioxide emissions and prevent the greenhouse effect: 1 ton of polyethylene (85.7% of organic carbon content) burning produces 3.14 tons of CO2, while 1 ton of fully biodegradable plastics (44% -55%) produces 1.8 ～ 2.02 tons of CO2 (2) promotes environmental protection, reduces white pollution, and reduces valuable land resources occupied by landfills.