线型聚(N-异丙基丙烯酰胺)的合成及性能研究

Preparation and Properties of Linear PNIPAm

通过自由基溶液聚合得到线型聚(N-异丙基丙烯酰胺),采用红外光谱、乌氏粘度计、凝胶渗透色谱、粒径分布仪等研究了引发剂用量对转化率、聚合物特性粘数、分子量及其分布和聚合物水溶液平均粒径的影响,并研究了反应时间对转化率的影响。研究结果表明:转化率、特性粘数、分子量和分子量分布宽度指数均随引发剂用量的增加先增大后减小,最大值分别为99.75%、0.3690mL/g、6.14×10-3g/mol(重均分子量)和2.7195。而聚合物水溶液的平均粒径则呈相反变化趋势,70℃下转化率在反应时间为7h时达到最大值99.75%。

A series of linear homopolymers of PNIPAm were prepared with the method of radical solution polymerization. Then the infrared spectrometer, Ubbelohde viscometer, gel permeation chromatography and laser particle size analyzer were applied to analyze the effects of the amount of initiator on the conversion rate, intrinsic viscosity, molecular weight, molecular weight distribution of the polymers and the average particle size of the polymers in aqueous solution. The influence of time of reaction on the conversion rate was also studied. The results show that when the amount of initiator increases, the conversion rate, intrinsic viscosity, molecular weight and molecular weight distribution all increase first and then decrease, the maximum of which are respectively 99.75%, 0.3690mL/g, 6.14×10^-3 g/mol （weight average molecular weight） and 2.7195, while the changing trend of the average grain diameter of the polymers in aqueous solution is opposite to the former ones. The conversion rate reaches its maximum when the reaction lasts 7 hours at 70℃.