轮胎胶应力诱导脱硫及对聚丙烯的增韧作用

Devulcanization of Ground Tire Rubber through High Stress-Induced Reaction and Its Application in Toughening Polypropylene

在轮胎胶粉的熔融挤出过程中添加线型高分子材料作为溶胀剂和承载流体,并通过提高双螺杆挤出机转速的高剪切应力诱导方法,研究了螺杆转速和挤出反应温度对轮胎胶脱硫共混物凝胶含量、熔体流动速率、溶胶特性黏数及红外光谱(FT-IR)的影响。结果表明,双螺杆挤出机的高剪切应力可诱发轮胎胶颗粒中交联网络的断链反应和氧化降解作用,引起脱硫共混物凝胶含量的明显下降、熔体流动速率的明显增加、溶胶特性黏数的明显减小及溶胶分子链中碳碳双键和醚键基团明显增加。在最佳脱硫反应条件下,所得脱硫共混物可使聚丙烯(PP)(J430)材料的缺口冲击强度由10.5kJ/m2提高至47.7kJ/m2。

The effects of screw rotation speed of twin screw extruder and extrusion temperature on the gel content, melt flow rate of the devulcanized ground tire rubber（DGTR）, and the intrinsic viscosity and fourier transform infrared spectra （FT-IR） of the sol of the blends were investigated by adding some thermoplastic material as bearing fluid during extrusion. The results show that high shear stress of the extruder can induce chain scission and oxidative degradation of the cross-linking network of the ground tire rubber, which decreases the gel content and increases the melt flow rate of the devulcanized blend. As a result, the intrinsic viscosity of the sol decreased and the content of C = C bond and ether bond in the sol increased. Under the optimum condition of 200℃ extrusion temperature and 1000 r/min screw rotation speed, the Izod impact strength of PP/DGTR blend goes up to 47.7 kJ/m2 comparing with neat polypropylene （PP） of 10.5 kJ/m2.