表面引发原子转移自由基聚合制备甲基丙烯酸甲酯接枝废胶粉及其表征

Preparation and characterization of poly(methyl methacrylate) grafted ground tire rubber via surface-initiated atom transfer radical polymerization

采用原子转移自由基聚合法研究了废胶粉(GTR)的表面化学接枝改性,包括2-溴异丁酰溴(BIBB)与GTR表面羟基的反应,以及形成的大分子引发剂引发甲基丙烯酸甲酯(MMA)的接枝聚合反应;用红外光谱和X射线光电子能谱仪、热重分析和扫描电子显微镜对接枝改性反应前后的GTR表面进行了表征。结果表明,GTR表面含有一定量羟基,其含量为3.84 mmol/g,它可与BIBB反应并实现引发剂在GTR表面的固定;GTR表面的大分子引发剂可引发MMA发生接枝聚合反应,当聚合反应进行到40 h时,改性GTR表面的接枝率可达到55%;GTR的失重过程为2步,而接枝GTR的失重过程为1步;改性后GTR的表面比未接枝GTR更加平滑,颗粒之间的结合更紧密。

The chemical graft modification of ground tire rubber（GTR） particles was studied via surface-initiated atom transfer radical polymerization.The whole reaction process included the reaction of 2-bromoisobutyryl bromide（BIBB） with hydroxyl on GTR and the graft polymerization of methyl methacrylate（MMA） initiated by macro initiator formed in above step.The immobilized and grafted GTR particles were characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectrometry,thermo gravimetric analysis and scanning electron microscopy,respectively.The results showed that there was some hydroxyl on the GTR surface and its content was 3.84 mmol/g,and the hydroxyl could react with BIBB and immobilize the initiator on the surface of GTR.The macro initiator on GTR surface could initiate the graft polymerization of MMA,and the graft ratio reached 55% when the polymerization proceeded for 40 h.The GTR lost its weight in two-step,while the GTR-g-MMA in one-step.The grafted GTR had smoother surface in comparison with unmodified GTR particles,and its particles bonded more tightly.