What are biodegradable materials and its classification
What are biodegradable materials?
Biodegradable materials include biodegradable natural polymer materials such as cellulose, starch, paper, etc., as well as biodegradable plastics obtained by biosynthesis or chemical synthesis.
Biodegradable plastics, means that in nature, such as sand, soil and/or conditions, and/or specific conditions such as composting conditions under the condition of anaerobic digestion or aqueous medium, and degradation caused by microbial action of the existence of nature, and eventually decomposed into carbon dioxide (CO2) and/or methane (CH4), water (H2O) and mineralization of the containing element inorganic salt, and the new biomass (such as the body of microorganisms, etc.).
It should be noted that the degradation of each biodegradable material, including paper, requires certain environmental conditions. If the degradation conditions are not available, especially under the living conditions of microorganisms, the degradation will be slow. At the same time, not every biodegradable material can degrade rapidly under any environmental conditions. Therefore, the treatment of biodegradable materials should be based on its environmental conditions, combined with the structure of the material itself to determine whether it is biodegradable materials. How to judge whether a material is biodegradable or not, a series of test methods and standards have been issued internationally and in China, which are answered in the standard questions.
What kinds of biodegradable plastics are there?
According to the source of raw materials, biodegradable plastics can be classified into two categories: biodegradable plastics and biodegradable plastics based on petrochemicals.
Biodegradable plastics can be classified into four categories: the first category is the plastics directly processed by natural materials. At present, biodegradable plastics produced by natural polymers in the market mainly include thermoplastic starch, bio-cellulose, polysaccharides and polyamino acids, as well as the products of their blending modification and chemical modification. The second type is the polymer obtained by microbial fermentation and chemical synthesis, such as PLA. The third type of polymers are those directly synthesized by microorganisms, such as PHA. The fourth category is the biodegradable plastics obtained by blending the above materials or by blending these materials with other chemically synthesized biodegradable plastics.
Biodegradable petrochemical plastics refer to the plastics obtained by chemical synthesis of the monomers of petrochemical products, such as polyterephthalic acid-butanedioic acid (PBAT), polybutanedioic acid (PBS), carbon dioxide copolymer (PPC), polyglycolic acid (PGA), etc.