一．Definition of Degradable Plastics
In nature such as soil, sandy soil, freshwater environment, seawater environment, specific conditions such as composting conditions or anaerobic digestion conditions;
Plastics that are degraded by the action of microorganisms that exist in nature, and finally completely degraded into carbon dioxide (CO2) or/and methane (CH4), water (H2O) and mineralized inorganic salts of elements contained in them, as well as new biomass (such as dead microorganisms, etc.).
At present, fully degradable polymers mainly include polylactic acid (PLA), polybutylene adipate/terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate-adipate (PBSA), polycaprolactone (PCL), polypropylene carbonate (PPC), polyglycolic acid (PGA), polydioxanone (PPDO), etc.
二．Classification of degradable plastics
(1) Soil-degradable plastics
(2) Compostable degradable plastics
(3) Degradable plastics in fresh water environment
(4) Anaerobic digestion of sludge to degrade plastics
(5) High solid anaerobic digestion to degrade plastics.
三．The difference between biodegradable plastics and ordinary plastics
Traditional plastics are mainly made of high-molecular compounds such as polystyrene, polypropylene, and polyvinyl chloride. The molecular weight of these high-molecular compounds reaches hundreds of thousands, and their chemical structures are stable and difficult to be degraded by microorganisms.
It takes 200 to 400 years for traditional plastics to degrade in the natural environment. Therefore, random discarding of traditional plastics can easily cause environmental pollution.
The main chain of degradable plastic polymers contains a large number of ester bonds, which can be digested and utilized by microorganisms, and finally decomposed into small molecules, which will not cause persistent pollution to the environment.
四．Biodegradable product labeling
Text ID:
Product type, product standard or degradation test method standard, product name (degradation environmental conditions + specific product name), product specification (length, width, thickness, weight), material, etc.
Graphic logo:
A green smiley face pattern with circular circles with arrows, double "j" (the first letter of degradation pinyin), material abbreviations (such as PBAT, PLA, PBS, etc.), names of six degradation environments, national standards and product names.
五．Quickly identify degradable plastic products
1.Look at the product implementation standard
At present, the materials of degradable plastics commonly used in the market refer to: polylactic acid (PLA), polyadipate/butylene terephthalate (PBAT), PLA+PBAT+starch (St).
Non-degradable materials refer to non-biodegradable polymer materials including polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), etc.
Biodegradable plastic bags are soft, wear-resistant, foldable and have a good texture.
The unit price of biodegradable plastic shopping bags in supermarkets is 0.7 yuan for small shopping bags and 1.2 yuan for large shopping bags, two to three times that of ordinary shopping bags.
