There are a number of new technologies in the reuse of waste resources

[China Packaging News] Recently, the second polymer materials industry-university-research forum hosted by Changan University was held in Xi'an. The reporter learned at the meeting that the new technologies developed by domestic universities and enterprises are making waste plastics, waste tires, waste textiles and other waste resources more green and efficient, and the products are more value-added.

Used electrical plastics: high value reuse

" Due to the long service life of electrical appliances, the aging performance of plastics is reduced. The conventional plastic modification and regeneration method is simple to granulate, the added value of blending modification technology is low, it is difficult to apply to mixed waste, and the performance is difficult to improve in the same direction, and the recycled materials Mainly for the low-end market, homogenization is serious. " Li Yingchun, deputy dean of the School of Materials Science and Engineering at North University of China, said.

Li Yingchun told reporters that they pioneered the chain extension method from the perspective of molecular repair, made full use of the characteristics of high aging waste plastics containing more active end groups, and added in-situ chain extension repair by adding chain extenders to prepare low-cost, High-performance recycled composite materials, impact strength of 6.3KJ / m2 , tensile strength of 43.7MPa , close to the level of the original material, comprehensively improve the comprehensive performance of recycled plastic waste.

At the same time, due to the similar appearance and density of HIPS ( high impact polystyrene ) and ABS in waste electrical plastics , it is difficult to separate, which affects the recycling. To this end, the team of Li Yingchun used R-HIPS and R-ABS blending methods to prepare various high-performance recycled polymer alloys for various types of low-aging waste materials by using a multi-component composite blending modification process to achieve high value of HIPS and ABS . Recycling enables the recycled composite materials to maintain the original plastic performance and value, rather than being degraded and used, which has greater economic and social benefits, and is currently looking for industrial cooperation.

It is understood that the amount of scrapped electrical appliances generated in China exceeds 200 million units each year , totaling 5 million tons. These home appliances all contain plastics mainly HIPS , ABS and polypropylene, accounting for more than 80% of the total .

Waste tires: low temperature green recycling

For the recycling of waste tires, Wang Shifeng, a researcher at Shanghai Jiaotong University, developed a low-temperature green nano-recycling technology for tire rubber. According to reports, the content of reclaimed colloidal sol prepared by this technology is 50-70% , which has better reinforcement and plasticity, which is better than traditional reclaimed rubber. At present, the reclaimed rubber prepared by this technology has been applied in Shuangqian Tire Company. By replacing natural rubber and carbon black by the same amount, the overall performance of the rubber compound remains basically unchanged.

" We use soybean vegetable oil as a softening agent, and rubber powder under the action of a catalyst, through low-temperature pyrolysis at 90-150 ℃ , swelling the rubber network. This new technology can not only weaken the force between molecular chains, but also isolate molecules Chain free radicals to achieve a high degree of degradation to produce tire reclaimed rubber. Vegetable oil as a softener is green and pollution-free, and the pollution of waste gas is low, the degree of regeneration is high, reaches the nanometer scale, the cross-linking decomposition effect is good, and it has both reinforcing and plasticizing effects. " The representative of the Wang Shifeng team said.

It is understood that 15 million tons of waste tire rubber is produced in China every year . The traditional regeneration technology breaks the cross-link bond by high-temperature ( higher than 200 ℃ ) high-pressure and strong shearing, which has the problems of high energy consumption, high cost, and secondary pollution during the regeneration process.
Waste textiles: transform into environmentally friendly products

In response to the problem that more than 80% of waste textiles are chemical fibers and the components are complex and difficult to degrade, Beijing Huan Textile Co., Ltd. jointly developed Handan Co., Ltd. and East China University of Science and Technology to jointly develop recycling technology for PET plastic polymer.

The company's general manager Li Shurun ​​pointed out that the new technology can produce PET polyester plastic alloy by recycling polyester in waste textiles through low-temperature solid-phase extrusion and reactive extrusion, etc., which can replace ABS engineering plastics for processing pipes and plates. At the same time, after sterilization and decolorization of waste cotton and linen fiber products under the action of strong oxidizing chemicals through the process of absorbent cotton, it is further processed into flame-retardant non-woven fabric products and green furniture products.

According to reports, in late May, the company's 100,000- ton / year waste textile recycling production line has been completed and put into production in Handan, Hebei.

It is understood that China consumes 50 million tons of textile raw materials every year , accounting for 52% of the world . The accumulated waste textiles exceeded 140 million tons, including about 98 million tons of chemical fiber and 42 million tons of natural fiber . At present, most of them have not been comprehensively utilized.