光学解偏振法测定高聚物的结晶速度

制成了光学解偏振法测定高聚物结晶过程的仪器,测试了聚丙烯、尼龙6等几种试样。本方法的优点是:样品用量少,测试温度范围宽,可以测定较快的结晶过程。由于设计了透射光强度自动控制电路,实验结果可靠,重复性好,并能自动记录。     

经不同程度降解聚丙烯的熔体流变性质

<正> 聚丙烯(PP)的热降解和化学控制降解法七十年代开始应用于聚合物工业加工过程。聚丙烯在高温下热降解,一般认为服从无规断链机理。随降解过程进行,分子量变小,分子量分布变窄,由定向聚合反应产生的特征性高分子量尾端降解最为显著。该过程往往可显著改善PP熔体加工性,因此研究降解过程对PP熔体流变性质的影响殊属     

聚丙烯腈纤维的预氧化过程的研究

本文通过差热分析、热机械行为、红外光谱、自由基浓度和模量的变化等实验,对采用均聚和共聚的两种聚丙烯腈原丝在氧化过程中出现的现象进行分析,可以看出均聚纤维的自由基反应引发环化较为明显,但由于存在水解反应,因此也存在离子型反应引发环化,而共聚纤维似以离子型引发为主。     

PERCOLATION TRANSITION IN ELECTRORHEOLOGICAL FLUIDS

The electric conductivity, dynamic modulus and yield stress of the developed electrorheolo-gical fluid (ERF) are measured at different volume fraction and different electric field strengthusing a modified Rheometrics Mechanical Spectrometer (Model 605). The percolation theory isintroduced to explain electrorheological effect and found that the ERF′s have the similarpercolated network structure as that of other ordinary suspensions with a critical volume fractionvalue independent of electric field strength. A master curve of dimensionless modulus againstdimensionless volume fraction is obtained. which shows that the essence of ER phenomenonactually is one kind of the second ofder phase transition.