轮胎胶应力诱导脱硫及产物结构与性能

Devulcanization of ground tire rubber by stress-induced reaction and its structure and mechanical properties of the revulcanized material

在轮胎胶粉(GTR)与三元乙丙橡胶(EPDM)的共混物熔融挤出过程中添加二硫化四甲基秋兰母(TMTD)和过氧化二异丙苯(DCP)作为脱硫反应促进剂,考察双螺杆挤出机的螺杆转速和挤出温度对再生胶(DGTR-EP-DM)的凝胶含量、溶胶分子链结构及再硫化材料力学性能的影响.结果表明:加入TMTD有助于反应体系中自由基的链转移反应,有助于对脱硫产物中较活泼双键的保护作用.当同时加入TMTD和DCP作为脱硫反应促进剂进行反应时,两者的协同作用有助于降解反应的进行,导致DGTR-EPDM中凝胶粒子尺寸的明显减小,并且其与丁苯橡胶(SBR)共混硫化胶力学性能的明显增加.在240℃和1 000 r/min的条件下,添加TMTD-DCP时,所得DGTR-EP-DM-SBR硫化胶的拉伸强度和断裂伸长率可分别达到19.2 MPa和554%.

The devulcanizing reaction performed during melt extruding of the mixture of ground tire rubber（GTR） with ethylene-propylene-diene monomer rubber（EPDM） was investigated through a high shear stress-induced reaction by increasing the screw rotation speed and reaction temperature.The results showed that the high shear stress comed from a twin screw extruder could stress-induce the chain scission and break up the cross-linking network of the ground tire rubber,thus leading to the decrease of the gel content of the devulcanized blends（DGTR-EPDM）.The higher the screw rotation speed and the reaction temperature,the more obvious the chain scission and the breakup of the cross-linking network,and the smaller the number and the size of the unfused gel particles in the devulcanized blends.Adding thiuram（TMTD） as an additive agent could increase the content of the double binds in the sol chains,and adding TMTD and peroxide（DCP） as a compound promoting agent could accelerate the devulcanization of the waste tire rubber,and lead to the decrease of the gel content and the size of the unfused gel particles in the devulcanized blends.As a result,in the presence of TMTD and DCP as a compounded additive at 240℃ and 1000r/min,the tensile strength and the elongation at break of the revlucanized blend DGTR-EPDM-SBR could reach to 19.2MPa and 554%.