| China is the world's largest rubber consuming country, but also a national short of rubber resources. How to resolve the sources of raw materials and rubber substitute materials, actively deal with waste rubber and full use of renewable resources and reduce environmental pollution is very important. In the rubber industry age of taking the natural rubber, synthetic rubber as raw material, as the third resource of the rubber industry, reclaimed rubber has done tremendous contributions in resolving the"black pollution"and developing rubber industry's circular economy. But there are still many problems in reclaimed rubber industry of China, such as technological method of regeneration is single, the performance of reclaimed rubber is not very good, secondary pollution is serious, too much energy consumption and so on. This paper has done some theoretical research and experimental analysis on achieving low-temperature regeneration of waste rubber, to improve the performance of reclaimed rubber and prevent pollution of the regeneration process and does research on the application of reclaimed rubber.Firstly, this contex dose some research on the technologies and methods of recycling waste rubber at home and abroad. The exploratory research and summary of waste rubber recycling theory is made. Research and design for the new eight- wing synchronous rotor is made. The new rotor used in mixer has strong shear force. The waste rubber with the untying cross-linking reagent in the mixing process could achieve regeneration of waste rubber under relatively low temperature. The finite element simulation of new eight-wing synchronous rotor is analyzed by polyflow software, including pressure field, velocity field, shear rate distribution, viscosity distribution, mixing index distribution. Waste rubber regenerated in low temperature is studied experimentally. With orthogonal experimental method, by optimizing the amount of regeneration agent,softening agent and sulfur, the mixing time and curing temperature and comparing the performance of reclaimed rubber, to determine the optimal combination formula and processing conditions. Last, through the experiment, the application of reclaimed rubber is studied and optimum conditions are determined.The work and the main achievements in this context are shown as followed:(1) The traditional rectangular rotor can not meet the regeneration process needs of strong shear force; this paper increases two pairs of rotor edges which designed on the basis of 4-wing synchronous rotor, while the top edge of the gap h0 set to 2mm;(2) The simulation results show that the new 8-wing synchronous rotor has a higher pressure difference, greater shear rate, lower composite index, which all show that the 8-wing synchronous rotor are capacity of shear tear, completely meet the needs of mechanical untying cross linking associated strong shear, laid the foundation for achieve regeneration of waste rubber in relative low temperature;(3) When the optimal combination is untying cross-linking agent 2phr, stearic acid 0.5phr, sulfur 0.5-1phr, mixing time 12min, curing temperature 160℃, the physical and mechanical properties of reclaimed rubber are best, temperature for the regeneration process is relatively low temperature of about 100℃;(4) Studies have shown that, homogenous compatible blends with good mechanical properties can be obtained from EPDM/R-EPDM by using sulfur and DCP as curing agent. 85/15 EPDM/R-EPDM blends are suitable for best composition and better compatibility. The micro-morphology of blends is observed by SEM. If high performance rubber products are manufactured, to add no more than 15 phr reclaimed rubber. If less demanding, large amounts of reclaimed rubber could be used. Comprehensive properties of rubber blends are better when the amount of DCP is 4phr, silica 50phr, curing time 3min. Compared with other factors, curing temperature has no obvious effect on properties of rubber blends, and generally it is 180-185℃. |
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