The processing and renewable resource technology of three abandoned PET plastic packaging bottles

The processing and renewable resource technology of three abandoned PET plastic packaging bottles

As one of the solid waste everywhere in life and industry, it is difficult for it to degrade in nature due to its stable physical and chemical characteristics. It is one of the important solid wastes currently needed to recycle treatment. At present, there are three main recycling technologies for abandoned PETs, namely the physical recovery method, chemical recycling method, and biological recovery method. The recovery of waste PET mainly adopts a physical recovery method. The chemical recovery method is used as auxiliary technology. The biological recycling method is still in the research stage.

Polyzylene glycol (PET) is the earliest line -type thermoplastic polymer that realizes industrialization. PET can maintain excellent physical mechanical properties within a wider temperature range, fatigue, excellent friction and aging resistance, excellent electrical insulation, stable for most organic solvents and inorganic acids, and low production. The processing performance is good, so it is widely used in the fields of plastic packaging bottle, film and synthetic fiber.

PET bottles have been widely used in the field of water and beverage packaging due to the advantages of light quality, high strength, good resistance to freshness, good climate resistance, good climate resistance, and convenient carrying. However, most PET products are disposable consumer products and are one of the most difficult plastics to recycle and use, that is, it is difficult to resource or reuse recycling through hot melt or solution. In recent years, a large number of abandoned PET products have become more prominent and have become one of the difficulties facing environmental protection of countries around the world.

The method of abandoned PET recycling can be divided into three categories: physical recovery method, chemical recovery method and biological recovery method. The physical recovery method is to physical mixing with other types of plastic products after recycling the abandoned PET without changing the PET molecular chain structure, thereby achieving the reuse of abandoned PET. Because PET is poorly compatible with other resins, the scope of waste PET physical recovery is limited. The chemical recovery method is to change the molecular chain structure of PET. Even if a large amount of ester bonds break, the molecular weight of PET is reduced, and the generated low -molecular weight products have a certain reaction activity to prepare new types of chemical raw materials. The biological recycling method uses biotechnology to degrade PET, or use PET as a source of food for biological foods to achieve the purpose of eliminating abandoned PET. At present, the main method of abandoned PET recycling is physical recovery.

1. Physical recycling method

1.1 Crossing it into plastic products after crushing

After collecting, classifying, cleaning, and crushing the abandoned PET bottle, there are two uses: one is to add other plastic products to reduce production costs; the other is The process is made into a new packaging container, but there is a safety problem with the packaging container that is processed and molded by this method, because the polyester is easy to decompose to generate acetaldehyde under high temperature bloating, which will cause the acetaldehyde content of the recycled polyester packaging container to exceed the standard The excessive standards of acetaldehyde will endanger human health, so the packaging container cannot be used for packaging food, medicine and other products.

1.2 Modified granules directly produce fiber

By adding the necessary additives to process the waste PET, it meets the quality standard of spinning raw materials. This recycled polyester material can be made into short fiber with a melting spinning method, and then processed into textiles or non -textiles, such as geoorgers, acupuncture carpets and interior decorative materials.

The physical recycling method is characterized by simple process, easy equipment operation, and low investment costs. The characteristics of the characteristic viscosity of polyester are adjusted through solid -state contraction, which makes the final product quality and stable. There are stricter requirements for separation and purification operations. The raw materials must not have too much impurities such as polyvinyl chloride, so as not to affect the final product quality. In addition, after melting waste polyester, its relative molecular weight will be reduced, which will increase the flexibility of the product and increase brittleness.

2 Chemical Recycling Method

The chemical recycling method, also known as the chemical cycle method, refers to the abolition PET with the action of the thermal chemical reagent to gather into a single body with reactive activity, or partially solve into a certain low -poetry or other chemicals. After the product is separated and purified, it can be used as a monomer to produce polyester, or as a raw material for synthetic other chemical products to achieve resource recycling. The chemical recovery method can generally be divided into hydrolysis, alcohol solution, ammonia solution, and other methods.

3 biological recycling method

The physical recovery method has broken the PET molecular chain, reduced molecular weight, and accompanied by certain impurities. Although the chemical recovery method can become a treasure, the response conditions are strict, the cost is high, and the improper treatment will produce additional pollutants. The use of the biological recycling method (such as microbial or degradase) degrades PET into a molecule, and then recycled. This method can not only solve the problem of PET waste, but also recover the materials required for PET synthesis.

PET macromolecules cannot enter the microbial body. Therefore, when the microbial degradation is degraded, some extracellular degradation enzymes must be secreted in vitro, degraded PET into small molecules, and then inhaled in the body. Essence

4 Conclusion

With the increase in the amount of various types of packaging materials such as beverage bottles, the amount of abandoned PET bottle increased rapidly, becoming a major public harm of environmental pollution, which has a adverse effect on human survival and development and the development of the environment itself. As a result, countries around the world are developing and developing the waste PET bottle recycling technology and made great progress. At present, the waste PET bottle recycling technology mainly includes physical recovery, chemical recovery, and biological recovery. Because the characteristics of the abandoned PET bottle are relatively stable, in terms of large -scale processing of abandoned PET plastic, the method of physical recovery is the main method of landfilling and incineration. The chemical recycling method is the auxiliary means. The research of microbial degradation PET has made rapid progress, and its recycling utilization rate has been effectively improved.