【摘要】 <正> 人们利用苯环在260nm区域的特征紫外吸收测定共聚物中聚苯乙烯(PS)链节含量时,常假设共聚物的紫外吸收仅来源于PS链节,且共聚物和PS均聚物具有相同的摩尔吸光系数.这些假定并不一定正确,即使共聚单体单元在260nm处不存在特征吸收,对共聚物吸收峰的位置和强度也有明显影响.不少研究者发现苯乙烯-甲基丙烯酸甲酯共聚物中,PS含量和吸光度不存在线性关系.E.J.Mechan发现丁二烯-苯乙烯共聚物中聚丁二烯链节在250～300nm范围内有一个宽的背景吸收.我们也发现在聚苯乙烯-g-十八烷基聚氧乙烯(PS-g-SPEO)接枝共聚物中,SPEO的背景吸收严重干扰了PS链节在260nm处的紫外吸收.为更多还原

【Abstract】 Because of the background absorbance of stearyl poly(ethylene oxide) , big errors arise when normal UV spectrometry is used to determine the polystyrene content of polystyrene-g-stearyl poly (ethylene oxide) (PS-g-SPEO). In order to eliminate the interference of SPEO, we developed the first derivative UV spectrometry for the quantitative composition determination of PS-g-SPEO. It was discovered that the undesirable background absorbance mentioned above could be completely eliminated and the compositions of PS-g-SPEO copolymers determined from the first derivative spectrometry coincide quite well with the data derived from elementary analysis. The results indicate that the nrst derivative UV spectrometry is a feasible and accurate method for the composition determination of polystyrene-based copolymers.更多还原