轮胎胶高剪切应力诱导脱硫反应的影响因素

采用在轮胎胶粉与三元乙丙橡胶(EPDM)混合物的熔融挤出过程中提高双螺杆挤出机螺杆转速的高剪切应力诱导方法,研究了轮胎胶粉品种和烷基酚多硫化物促进剂对轮胎胶脱硫共混物的凝胶含量、溶胶分子链结构及脱硫共混物共混丁苯橡胶再硫化材料力学性能的影响。试验结果表明,胶粉品种对所得脱硫共混物溶胶中的双键含量及再硫化材料的拉伸强度具有重要影响;烷基酚多硫化物促进剂420和450具有明显促进脱硫反应和抑制交联副反应的作用,有效减小再硫化材料凝胶粒子尺寸,聚合型促进剂450兼具有抗氧化降解和抑制加成副反应的功能。

Effect of High Shear Stress Coming from Twin Screw Extruder on Devulcanization of Ground Tire Rubber

The devulcanization reaction of ground tire rubber induced through a high shear stress coming from increasing screw rotation speed during melt extruding of the mixture of ground tire rubber(GTR) with ethylene-propylene-diene monomer rubber(EPDM) was investigated by adding polysulfide as promoting agent and changing the grade of GTR.The results show that the grade of ground tire rubber has an important influence on the reaction and the chain structure of the devulcanized blend with styrene-butadiene rubber(SBR).The promoting agents of polysulfide 420 or 450 can suppress the cross-linking reaction,accelerate the devulcanization during the extruding process and increase the tensile strength and elongation at break of the revulcanized blend SBR/(DGTR/EPDM),leading to decrease the size of unfused gel particles in the devulcanized blends.Especially,the promoting agent of polysulfide 450 can further prevent the oxidized decomposition and avoid the additive reaction of the double binds in reaction mixture during extruding process.