PEG6000溶液超声化学反应机理的初步研究

采用不同电功率的超声波处理了聚乙二醇(PEG6000)溶液。凝胶渗透色谱(GPC)分析超声处理后的PEG溶液发现,当超声电功率超过250W时,PEG分子量随超声波作用强度的增大而减少,随超声波作用时间的延长而增大;在电功率超过250W超声波作用下,傅立叶红外光谱(FT-IR)分析表明,组成PEG的单体没有明显改变,但是,羟基含量分析表明,PEG固体样品中的羟基含量有所减少。结合实验结果,根据高分子化学、有机化学和超声化学中相关理论对PEG超声化学反应机理进行了探讨,认为:当超声波作用于PEG溶液时,同时存在有PEG的缩水聚合反应和自由基降解反应,当频率为20-25kHz、电功率为250-600W的超声作用于PEG6000溶液时,缩水聚合反应占主导地位。

Preliminary study on sonochemical reaction mechanism in PEG6000 solutions

The PEG6000 solution was treated by ultrasound with various electric powers. The molecular weights (MW) of the treated PEG were analyzed by GPC and it was found that the MW of PEG decreased with the intensity of ultrasound, but increased with the ultrasound irradiating time when the electric power of ultrasound exceeded 250W. For the function group composition of treated PEG as analyzed by FT-IR, the monomer which constitutes PEG had no evident change, but the OH concentration of solid treated PEG decreased when the electric power of ultrasound exceeded 250W. Based on these experiment results, mechanism of the chemical reaction in PEG6000 solution under radiation of ultrasonic wave was discussed by the application of the theories of polymer chemistry, organic chemistry and sonochemistry. It is believed that the polymerization reaction and the radical degradation reaction exists simultaneously in the PEG6000 solution under radiation of ultrasonic wave, but the former process dominates when the frequency of the radiating ultrasonic wave ranges from 20kHz to 25kHz and the electric power ranges from 250W to 600W.