| This paper first explored the feasibility and safety of the microwave regeneration process of waste tire rubber powder(a certain metal content of the whole tire rubber powder) and then we explored the best regeneration process of different kinds of waste tire rubber powder with various particle size by microwave;Secondly, we studied the effect of environment-friendly softeners with different amount and polarity on the microwave regeneration process and the properties of reclaimed rubber;Finally, we explored the application of supercritical carbon dioxide in blending of waste rubber powder with regeneration agents, which was prepared for microwave regeneration, and the microwave-electric heating regeneration process in order to get the best the best conditions for both. The main contents and conclusions are as follows:Firstly, we found it is feasible and safe to regenerate waste tire rubber powder by microwave through heating whole tire rubber powder by microwave. The waste rubber powder with bigger particle size showed faster heating rate and the whole tire rubber powder was heated slower than the tread rubber powder. The tread rubber powder with a mass of 160 g and thickness of about 20 mm was with the best regeneration performance when treated with 5 min by microwave(2450 MHz, 800W), while the whole tire perform best when treated with 6 min.Secondly, we studied the effect of environmental-friendly PAX and softener at different amount and PAX/glycerin with various ratio on whole tire rubber powder devulcanized by microwave. The results showed that, the regeneration temperature decreased due the join of PAX and environment-friendly softeners, meanwhile they were both beneficial for uniformity of regenerated waste rubber. When 10 phr PAX or 15 phr TDAE was added, the properties of reclaimed rubber were best, and it performed better with PAX. Then we found that the addition of glycerin could increase the regeneration temperature, heating rate, processing performance of waste rubber powder with TDAE while it decreased its mechanical performance slightly.Thirdly, we used supercritical carbon dioxide to blend waste rubber particle with regeneration agent and then regenerated it by microwave process and we studied the influence of temperature, pressure and temperature on the performance of regenerated waste rubber. The results showed that regeneration agent permeated merely and the permeation extent reached the maximum and the regenerated waste rubber performed best when treated with supercritical carbon dioxide at the condition of 80℃, 15 MPa, 30 min or 80℃, 20 MPa, 20 min.Finally, we combined microwave and electric heating regeneration process to regenerate the whole tire rubber powder and tread rubber powder. Results showed that the whole tire rubber powder treated with microwave for 6 min and insultated in the kettle with electrical heating for 7-9 min at 190℃ or 5 min at 200℃ exhibited the best performance. While, the tread rubber powder treated with microwave for 5 min and insultated in the kettle with electrical heating for 8 min at 190℃ performed best. We also balanced both advantages and disadvantages of the three methods and found that microwave-electric heating regeneration process with high efficiency and lower cost is the best one among them according to the better performance of reclaimed rubber. |
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