The application prospect of the most pyrolytic pac

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The application prospect of degradable packaging materials is broad.

now, the annual plastic output in the world has reached 1*10t, and plastic products are about 5*108t. Antie calculated that its consumption had exceeded that of metal materials in the 1980s. Plastic has many excellent characteristics, such as many raw materials, easy production, excellent performance, low cost, light weight, easy molding, non-corrosion, easy coloring and so on. It is widely used in various fields of packaging, making it an excellent substitute for metal, wood, natural fiber and natural rubber

with the continuous increase of the output and consumption of plastics, the following problems are also increasing, mainly the continuous increase of waste plastics. Generally speaking, there are three aspects of waste plastics: one is polyethylene, which is mainly used to make handbags and agricultural films; The other is polypropylene,; Generally used as packing belt; There is also polystyrene, which is used as foam shock-absorbing material for packaging, fast-food lunch boxes, packaging fillers, etc. These three components account for 70% - 80% of waste plastics. Nearly half of the new plastic products will become waste plastics after two years. Waste plastics are very stable in the natural environment, not easy to corrode and degrade, and have a very serious impact on the environment, forming a typical white pollution. Therefore, in recent years, in the plastic industry, it is natural to call for the emergence of functional plastics that can be degraded

according to the degradation mechanism, the degradation of plastics can be divided into: chemical degradation, thermal degradation, oxidative degradation, radiation degradation, photodegradation, mechanical degradation, and biodegradation

biodegradable plastics can only be completely degraded into plastic materials through the action of natural microorganisms, such as bacteria and molds. Generally, plastic materials mainly due to the high hardness of bars and low molecular compounds have the following characteristics: they can be made into compost and return to nature; Due to degradation, the volume is reduced, extending the service life of the landfill site; There is no burning problem of ordinary plastics; It can reduce the harm of wild animals and plants caused by random discarding; Convenient storage and transportation; Widely used and other advantages

according to the degradation mechanism and destruction form, biodegradable plastics suitable for the packaging industry can be divided into: fully biodegradable plastics and biodegradable (or collapse to reduce the collapse of pulsating components) plastics. Under the action of microorganisms, fully biodegradable plastics can be completely decomposed into small molecular compounds such as carbon dioxide and water within a certain period of time, while completely destructive plastics can only be decomposed into scattered fragments. According to the manufacturing method, biodegradable plastics can be divided into natural polymers, microbial synthesis and artificial synthesis

natural polymer materials can be used as explanation materials, such as cellulose, starch, chitin, lignin, etc. From nature, tourists are biodegradable and natural, but their province is not plastic, so they are formed into degradable polymer materials through natural chemical modification or blending with polymers, copolymerization modification or adding to polymers

microbial synthesis mainly uses bioengineering to synthesize biodegradable polymer materials, and has obtained cheaper degradable plastic products, the main component of which is microbial polyester. For example, by using genetic engineering to dry the leaves of poplar, grind them into fine powder, and then extract the chloroplasts, the parent particles of polyalkyl butyric acid (PHB) can be obtained from the chloroplasts of poplar, so as to obtain PHB degradable plastics

there are biodegradable polymer materials and photodegradable polymer materials in synthetic biodegradable chemical synthetic polymer materials. Among them, biodegradable polymer materials include polyvinyl alcohol (PVA) through state, water-soluble polymers such as polyethylene glycol and caprolactone (PCL). At present, polyester polyamide copolymer (Cpae), aliphatic and aromatic copolyesters (CPE), poly amino acids, polyorthoesters, polyester polyurethane, etc. have reached the commercial development and achieved the maximum environmental protection

source: Internet

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