超声辐照引发MMA微乳液聚合动力学研究

用自由基捕捉剂N,N-二苯基-2,4,6-三硝基苯肼基(DPPH)进行超声辐照引发甲基丙烯酸甲酯(MMA)微乳液聚合引发过程的动力学研究,结果表明,所得速率常数比超声辐照引发纯单体聚合的速率常数大一个数量级,说明超声辐照在微乳液聚合体系中的引发作用远远强于本体聚合;得到的表观活化能为正值,说明升温有利于超声辐照引发微乳液聚合.对聚合过程动力学的研究表明,引发剂用量决定聚合反应速率曲线恒速期的长短.

Studies on Kinetics of Ultrasonic Induced Microemulsion Polymerization of MMA

In this paper, the radical scavenger DPPH was used to study the kinetics of ultrasonic induced microemulsion polymerization of MMA. Rate constants and apparent activation energy were obtained under various temperatures and power outputs. Compared with the results of ultrasonic induced bulk polymerization of MMA, the rate constants in this study were much higher, indicating that there was higher initiation efficiency of ultrasonic irradiation in emulsion system than in pure monomers. The kinetics results of ultrasonic induced microemulsion polymerization were expected to be suitable for the ultrasonic induced emulsion polymerization for their similar initiation mechanism. The kinetics during the polymerization was also investigated, and the result proved that there was an extended region of constant rate when the concentration of radicals was lower. Therefore, the results of the study on the kinetics of ultrasonic induced microemulsion polymerization of MMA provided a theoretical foundation for deeply understanding the mechanism of ultrasonic induced microemulsion and emulsion polymerization.