动态硫化制备高密度聚乙烯/脱硫轮胎胶粉热塑性弹性体

Preparation of Thermoplastic Elastomers Based on High Density Polyethylene and Ground Tire Rubber Through Dynamic Vulcanization

采用固相力化学技术实现了废旧轮胎橡胶(GTR)的脱硫化及与高密度聚乙烯(HDPE)的复合,并采用动态硫化技术成功制备了HDPE/GTR热塑性弹性体(TPE)。结果表明,经力化学碾磨后,胶粉的凝胶含量显著降低。碾磨20次后,共混材料的拉伸强度由碾磨前的5MPa提高到8.6MPa;扯断伸长率由碾磨前的9.7%提高到63.3%。经动态硫化制备热塑性弹性体,材料的力学性能进一步提高,碾磨20次的复合粉体制备的TPE拉伸强度和扯断伸长率分别提高到10.6MPa和76.5%。所制备的TPE均保持了橡胶良好的回弹性,拉伸永久变形均保持在20%以内。扫描电子显微镜(SEM)研究表明经力化学处理制备的HDPE/GTR热塑性弹性体两相间具有良好的界面结合。

The devulcanization of ground tire rubber （GTR） and its good dispersion in high density polyethylene （HDPE） were realized through solid state mechanochemical milling. Thermoplastic elastomer （TPE） was subsequently prepared based on the HDPE/GTR composite powder through dynamic vulcanization. The substantial decrease of gel fraction after mechanochemical milling confirmed the partial devulcanization of GTR. The mechanical properties were remarkablely improved after mechanochemical treatment. After 20 cycles of milling, the tensile strength of HDPE/GTR blends increased from 5 MPa to 8.6 MPa, the elongation at break increased from 9.7% to 63.3%. The mechanical properties of the blends were further improved through dynamic vulcanization. The tensile strength and elongation at break of the TPEs was improved to 10.6 MPa and 76.5%, respectively. Permanent set of the TPEs was kept in the range of 20%, and they preserved the well elasticity of the rubber. SEM studies further confirmed the improvement of the interfacial compatibility between HDPE and GTR after mechanochemical milling and dynamic vulcanization.