亚临界流体挤出法复合诱导SBR基轮胎胶脱硫化及 再硫化材料力学性能

在SBR基轮胎胶(GTR)与三元乙丙橡胶（EPDM）混合物的熔融挤出过程中，采用改变亚临界流体品种和提高螺杆转速的方法，研究了亚临界流体（水，乙醇，丙醇）、螺杆转速、烷基酚多硫化物促进剂（450）以及温度对脱硫共混物（DGTR/EPDM）凝胶含量、门尼粘度、溶胶红外光谱及脱硫共混物共混丁苯橡胶（SBR）再硫化材料（SBR/(DGTR/EPDM)）力学性能的影响，对再硫化材料的试样断面形貌也进行了SEM观察。实验结果表明：亚临界流体（水，乙醇，丙醇）作为一种溶胀剂和反应性介质能够很好地促进脱硫反应，提高交联键断裂的选择性，降低脱硫产物的凝胶含量和凝胶颗粒尺寸并明显提高脱硫共混物共混丁苯橡胶再硫化材料的力学性能，其中亚临界乙醇的作用最显著。当450作为一种脱硫促进剂，在最优亚临界乙醇挤出反应条件（200℃，1.6 MPa，600 rpm）下，脱硫共混物共混丁苯橡胶分别达到丁苯生胶混炼硫化材料拉伸强度（24.0MPa）和断裂伸长率（356%）的99.6%和209%。

Effect of Shear Stress and Subcritical Fluids on Devulcanization of SBR-Based Ground Tire Rubber in a Twin Screw Extruder

The devulcanization reaction of styrene butadiene rubber (SBR)-based ground tire rubber (GTR) in GTR/ethylene-propylene-diene monomer rubber (EPDM) blend was investigated through a compound-induced reaction by increasing the screw rotation speed and being in the presence of different subcritical fluids(water, ethanol and propanol). The effects of the screw rotation speed, different subcritical fluids, the promoting agents or temperature on the gel content, Mooney viscosity, FT-IR spectra of the sol of the devulcanized blends (DGTR/EPDM) were measured, and the mechanical properties and microstructures of the revulcanized blend ((DGTR/EPDM)/SBR) were characterized. The results show that subcritical fluids as a swelling agent and reaction medium promotes the devulcanization reaction, increases the selectivity of the crosslink breakage, reduces the gel particle size of the devulcanized blends and significantly improves the mechanical properties of the revulcanized SBR/(DGTR/EPDM) blends. Among different subcritical fluids(water, ethanol, propanol), the effect of subcritical alcohol is significantly obvious. When 450 is added as promoting agent at the best reaction condition in subcritical alcohol (200oC, 2.2MPa and 600rpm), the tensile strength and elongation at break of the revulcanized SBR/(DGTR/EPDM) blends reach to 99.6% and 209% of vulcanized SBR (24.0MPa, 356%) respectively.