Application Overview and development status of the

The application and development status of degradable plastics

the plastic industry has developed rapidly. At present, the total output of plastics in the world has exceeded 170 million tons. Its use has penetrated into all sectors of the national economy and all fields of people's life. It has become one of the four pillar materials together with steel, wood and cement. However, the disadvantage of plastic is that it is difficult to degrade in the natural environment or garbage dump after use, so it becomes garbage that pollutes the environment. The data shows that the mass fraction of plastic in municipal solid waste has reached more than 10%, while the volume fraction is about 30%. The development of degradable plastics can reduce white pollution and has significant economic and social benefits

at present, the research and development of degradable plastics are very active, and some of them have entered industrial production. On the whole, the current degradable plastics still need to be further studied on technology, improve performance, reduce costs, expand applications and gradually put into the market

at present, the countries producing degradable plastics mainly include the United States, Italy, Germany, Canada, Japan, China, etc. The United States is one of the major countries developing degradable plastics, and there are mainly more than a dozen units, such as the plastic degradation Research Consortium (P will DRC all kinds of waste metals), biological/environmental degradable plastics research association (beops), etc. its purpose is to carry out the synthesis of degradable materials, processing technology, degradation test, testing technology and method standard system. In recent years, Japan has successively established a biodegradable plastics research association and a review committee on the practicality of biodegradable plastics. Japan's Ministry of trade and industry has taken biodegradable plastics as the "fourth type of new materials" after metal materials, inorganic materials and polymer materials. Bhre eurae in Europe has established a perfect degradation evaluation system for biodegradable plastics

in recent years, the research and development of fully biodegradable plastics has been the most active in developed countries. It is reported that the annual output of fully biodegradable plastics in the world was about 30000 tons in 1998. By 2001, the output of the United States, Western Europe and Japan had increased to about 70000 tons. At present, biodegradable products abroad are mainly fully biodegradable plastics, which will still be the medium and long-term industrial development direction in the future

degradable plastics are mainly divided into photodegradable plastics, biodegradable plastics and photodegradable plastics according to their degradation mechanism

there are two types of photodegradation technology, synthetic and additive, that have been used in the force measuring mechanism in foreign countries. The former is to introduce photosensitive groups into the main chain of olefin polymer, and the latter is to add photosensitive chemical additives to the polymer. At present, the research on ethylene copolymer photodegradable polymers is the most. The research shows that polyethylene can be absorbed and degraded by microorganisms in soil after it is degraded into oligomers with molecular weight less than 500, which has good environmental safety. DuPont, Dow Chemical, Bayer and other companies in the United States and the University of Toronto in Canada have used this technology to achieve industrial production

biodegradable plastics refer to polymer materials that can be quickly degraded through the life activities of microorganisms in the natural environment. According to its degradation characteristics, it can be divided into completely biodegradable plastics and biodegradable plastics. According to its source, it can be divided into natural polymer materials, microbial synthetic materials, chemical synthetic materials, mixed materials, etc

natural polymer type is a biodegradable material prepared from natural polymer materials such as starch, cellulose, chitin and protein. This kind of material has rich sources, can be completely biodegradable, and the product is safe and actually non-toxic, which has been paid more and more attention. Warner Lambert developed a new resin made of 70% amylopectin and 30% amylose powder, which has good biodegradability and can replace various biodegradable materials used in agriculture. In Japan, cellulose derivatives and deacetylated polysaccharides are compounded, and the film is prepared by tape casting method. Its strength is similar to that of polyethylene film, and it can be completely degraded in about two months. Although natural polymer materials have complete biodegradability, their thermal and mechanical properties are poor, which can not meet the performance requirements of engineering materials. Therefore, the current research direction is to obtain natural high separation degradable plastics with use value through natural polymer modification

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