Recently, the second Forum on Polymer Material Production and Research sponsored by Chang’an University was held in Xi’an. The reporter learned at the meeting that the new technologies developed by universities and enterprises in China are waste materials such as waste plastics, used tires, and waste textiles. The reuse of the product is more green and efficient, and the product is more expensive.
Old Electrical Appliances: High Value Reuse
'Because of the long service life of electrical appliances, the aging properties of plastics have declined. It is simple to use conventional plastics to modify and regenerate the granulation. The low value-added of blended modification technology makes it difficult to apply to miscellaneous wastes, and it is difficult to improve the performance in the same direction. Mainly for the low-end market, homogeneity is serious.' said Li Yingchun, vice president of the School of Materials Science and Engineering at North University.
Li Yingchun told reporters that they pioneered the chain extension method from the point of view of molecular remediation, and took full advantage of the fact that high-ageing waste plastics contained more active end groups, and added chain extenders to achieve in-situ chain extension repairs to produce low-cost products. High-performance recycled composite material, 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 the reuse of waste plastics.
At the same time, due to the similar density and appearance of HIPS (High Impact Polystyrene) and ABS in waste electrical plastics, it is difficult to separate them and affect recycling. For this reason, Li Yingchun's team adopted the method of blending R-HIPS and R-ABS. , Aiming at all kinds of low-ageing wastes, adopting multiple compound blending modification process to prepare high-performance recycled polymer alloys, realizing high-value recycling and reuse of HIPS and ABS, so that the regenerated composite materials can maintain the original plastic properties and value. , Instead of degraded use, with greater economic and social benefits, is currently looking for industrial cooperation.
It is understood that the amount of waste electrical appliances scrapped annually in China exceeds 200 million units, a total of 5 million tons. These household appliances contain plastics mainly HIPS, ABS and polypropylene, accounting for more than 80% of the total.
Scrap Tires: Low-temperature green regeneration
For the regeneration of discarded 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 regenerated colloidal sol prepared by this technology is 50-70%, with good reinforcement and plasticity. Traditional reclaimed rubber. At present, the reclaimed rubber prepared by this technology has been applied by Double Money Tire Co., Ltd. It replaces natural rubber, carbon black, etc. by equal amounts, and the overall performance of the rubber material remains basically unchanged.
'We use soybean vegetable oil as a softener, and the rubber powder under the action of the catalyst, through a low temperature pyrolysis of 90-150 °C, swells the rubber network. This new technology can not only weaken the forces between the molecular chains, but also can isolate molecules Chain free radicals, to achieve a high degree of degradation, the preparation of tire reclaimed rubber. Vegetable oil as a softener green pollution, and less pollution of the exhaust gas, a high degree of regeneration, reach the nanoscale, cross-linking decomposition effect is good, both reinforcing and plasticizing effect. ' Wang Shifeng's team representative said.
It is understood that 15 million tons of used tire rubber produced in China each year. The traditional regeneration technology breaks the crosslink bonds through high-pressure (200°C or more) high-pressure shearing. There is high energy consumption, high cost, and secondary pollution during the regeneration process. problem.
Waste Textiles: Transforming Environmental Products
In view of the fact that more than 80% of the waste textiles are chemical fibers, and the components are complex and difficult to degrade, Jinghuan Textile Recycling Co., Ltd. and East China University of Science and Technology jointly developed a technique for recovering the plasticity of PET plastic polymers.
The general manager of the company, Li Shurun, pointed out that the new technology can recover polyester from waste textiles by producing low temperature solid phase extrusion, reactive extrusion, etc. PET polyester plastic alloys can be used instead of ABS engineering plastics for processing pipes, plates, etc. Simultaneously through the absorbent cotton process , After the strong oxidizing chemical agents disinfect and decolorize the waste cotton and fiber products, further processing into flame-retardant non-woven products, green environmental protection furniture products.
According to reports, in late May, the company’s 100,000-ton/year waste textile recycling production line was completed and put into operation in Hebei Handan.
It is understood that China consumes 50 million tons of textile raw materials each year, which accounts for 52% of the world's total. There are more than 140 million tons of waste textiles produced, including 98 million tons of chemical fibers, and about 42 million tons of natural fibers. Most of them are not yet available. Get comprehensive utilization.