含氧光敏引发体系的研究——II.BP/TEA/O_2引发体系中氧的加速作用

研究了二苯酮(BP)/三乙胺(TEA)/氧体系引发MMA聚合反应中氧的加速作用。体系中保持比较大的TEA/O_2浓度比值,是实现氧加速作用的必要条件。实验结果得出:系统中氧通过光氧化生成过氧化物的速度Vo_2=KBP]TEA]~(0.8)。由于过氧化物的光敏分解,使初级自由基得到增殖。从测定的K_p/K_t~(1/2)值,说明存在初级自由基的终止作用。测定了光氧化动力学方程的数据并讨论了机理。

STUDY OF THE PHOTOSENSITIZED INITIATION SYSTEMS CONTAINING OXYGEN——Ⅱ. The Accelerating Effect of Oxygen in the Benzophenone/Triethylamine/Oxygen Initiation System

The accelerating effect of oxygen in the benzophenone/triethylamine/oxygen (BP/ TEA/O2) system was studied. It is necessary to keep high concentration ratio of TEA/O2 in order to achieve the accelerating effect. Experimental results indicated that oxygen in the system through photooxygenation reaction transformed to peroxides. The rate of oxygenation depended on BP] and TEA]0.8. Subsequent photosensitized de-composotion of peroxides led to an increase in forming primary radicals. Prom the detennintd KP/Kt1/2 value it may be interpreted as the evidence of the primary radical termination. The kinetic orders related to photooxidation of oxygen have been determined and the corresponding reaction mechanisms are also discussed.