中文摘要：

采用光-示差扫描量热法（P-DSC）和光-流变学（P-Rheology）技术,测定了丙烯酸酯/液晶体系的光聚合反应动力学和凝胶化时间.基于自催化模型和凝胶时间-温度关系,计算了体系的光聚合反应速率常数和活化能,探讨了单体结构与组成、反应温度对体系光聚合动力学的影响,并研究了聚合物分散液晶（PDLC）的电光响应行为与相分离结构对光聚合动力学的依赖性.结果表明,升高反应温度、增加体系的单体反应活性和平均官能度,均提高了体系的光聚合速率常数,缩短了光聚合凝胶时间.随着单体反应活性和平均官能度的提高,体系的光聚合反应活化能明显降低,且凝胶化前的光聚合反应活化能低于光聚合全过程的平均反应活化能.当液晶含量为50%时,形成的PDLC呈亚微米尺度的双连续相结构.随着光聚合反应温度的升高,光聚合速率加快,导致凝胶时间缩短、相分离程度降低,使PDLC中液晶相尺寸变小、聚合物网络致密化,PDLC的弛豫时间延长、饱和电压降低,而开启时间和阈值电压变化不大.

英文摘要：

Photopolymerization kinetics and gelation time of acrylate/liquid crystal syrups were characterized by photo-differential scanning calorimetry （P-DSC） and photo-rheology technology （P-Rheology）, respectively. The effects of chemical structure and composition of acrylate monomers, and photopolymerization temperature on the kinetics of these syrups were discussed on the basis of the correlation between gelation time and temperature, as well as the polymerization rate constant and activation energy which were calculated from the autocatalysis model. Furthermore, the effects of photopolymerization kinetics on the electro-optical properties and phase-separated structure of the polymer dispersed liquid crystals （PDLCs） were studied. The results indicated that the polymerization rate constant increased and the gelation time decreased with increasing the photopolymerization temperature, the monomer reactivity, and the average functionality of monomers. In addition, the photopolymerization activation energy decreases with increasing the reactivity and average functionality of monomers. Meanwhile,the activation energy before gelation is lower than the global one. When the LC content is 50 wt% , the PDLCs show a bicontinuous phase structure at a submicron scale. Also, the gelation time is significantly shortened with increasing the photopolyemerization rate and temperature,leading to smaller LC domains and denser polymer networks in PDLCs. Consequently, the turn-off time is prolonged and the saturation voltage of the PDLCs lowers,whilst their turn-on time and threshold voltage show little variation.