丙烯酸酯/液晶复合体系的光聚合动力学  

Kinetics of Photopolymerization for the Acrylate/Liquid Crystal Mixture

作　　者：史小靖[1] 彭海炎[1] 廖永贵[1] 解孝林[1,2] 

机构地区：[1]华中科技大学化学与化工学院 [2]国家防伪工程技术研究中心,武汉430074

出　　处：《高等学校化学学报》2011年第6期1407-1411,共5页Chemical Journal of Chinese Universities

基　　金：国家杰出青年基金(批准号:50825301)资助

摘　　要：采用光差示扫描量热分析方法研究了以2,4,6-三甲基苯甲酰基-二苯基氧化膦(TPO)为光引发剂,丙烯酸异辛酯(EHA)和三羟甲基丙烷三甲基丙烯酸酯(TMPTA)为单体,丙烯酸酯/液晶(P0616A)复合体系在-40～80℃的光聚合动力学.研究结果表明,丙烯酸酯/液晶复合体系光聚合速度明显高于传统的自由基聚合反应体系,转化率在约50 s的时间内即达到增长平台,聚合反应速率和表观动力学常数在聚合过程中均存在最大值.随着反应温度的升高,体系的最终转化率和最大聚合反应速率(Rp,max)均明显提高;当反应温度高于20℃后,其增长均趋于平缓.随着体系中液晶含量的增加,体系的Rp,max呈下降趋势,聚合反应转化率随时间的增长速率较慢,但是最终转化率差别不大,均接近80%.随着UV光强的增加,体系的Rp,max和最终转化率均明显提高,体系的阈值光强约为4 mW/cm2.而随着体系平均官能度的增加,体系的Rp,max和最终转化率则呈下降的趋势.Photo-differential scanning calorimetry（P-DSC） was used to characterize the photopolymerization kinetics for a mixture of 2-ethylhexyl acrylate（EHA）,trimethylolpropane trimethacrylate（TMPTA） and nematic liquid crystal（LC,P0616A） with 2,4,6-trimethylbenzoyldiphenyl phosphine oxide（TPO） as photoiniator at different reaction temperatures（-40-80 ℃）.The results revealed that photopolymerization is faster than the traditional free radical polymerizations,the conversion of the above mixture reaches the plateau in about 50 s,and there are maxima in photopolymerization rate and apparent kinetic constant.All final conversion and maximum photopolymerization rate（R_p,max） increase with the reaction temperature.When the reaction temperature rises to 20 ℃,the above values increase slightly.In addition,Rp,max decreases with increasing LC content,and the conversion increases slowly with increasing time.Noticeably,the final conversions for the above mixtures have littile difference at different LC contents,and all of them are closed to 80%.With increasing UV intensity,both Rp,max and the final conversion increase obviously,and the threshold value of UV intensity is 4 mW/cm2.However,Rp,max and the final conversion tend to decrease with increasing the average functionality of monomers.

关 键 词：液晶 丙烯酸酯 光差示扫描量热 光聚合动力学 

分 类 号：O631[理学—高分子化学]