丁腈橡胶/聚丙烯热塑性硫化胶的等温结晶行为

分别采用超细全硫化丁腈橡胶颗粒(UFNBR)与聚丙烯(PP)直接共混、动态硫化丁腈橡胶(NBR)和PP、反应增容法制备了UFNBR/PP热塑性硫化胶(TPV)、NBR/PP TPV和NBR/端氨基液体丁腈橡胶(ATBN)/PP/马来酸酐接枝聚丙烯(MP)TPV,通过差示扫描量热法表征了3种TPV的等温结晶行为,并利用X射线衍射仪研究了3种TPV中PP的晶体结构。结果表明,NBR均对PP的结晶起到成核剂的作用,加快了PP的结晶速率,在3种TPV中,NBR/ATBN/PP/MP的结晶速率最快;TPV的等温结晶行为可以用Avrami方程来表征;3种TPV未改变PP的晶型,仍为单斜晶系的α-PP晶型结构。

小粒径胶粉/HIPS复合材料的制备及性能研究

采用丙烯腈-丁二烯-苯乙烯共聚物(ABS)高胶粉(H-181)和超细全硫化丁苯橡胶胶粉(VP-108)分别对高抗冲聚苯乙烯(HIPS)进行机械共混改性,利用通用聚苯乙烯(GPPS)来调节橡胶相的含量,制备了5种HIPS/H-181-GPPS和5种HIPS/VP-108-GPPS复合材料,探讨了不同用量的两种小粒径胶粉,对HIPS复合材料光学性能和力学性能的影响。测试结果显示,当填充H-181胶粉时,光泽度达到最大值78°。当填充VP-108胶粉时,光泽度达到76°。与HIPS825相比,添加H-181和VP-108胶粉,复合材料的光泽度分别提高95%和90%。HIPS/H-181-GPPS和HIPS/VP-108-GPPS复合材料拉伸强度分别提升43.3%和28.3%,弯曲强度分别提升96.9%和37.7%,弯曲模量分别提升100.3%和21.1%,维卡软化温度分别提升34%和32.3%。

The abnormal behavior of polymers glass transition temperature increase and its mechanism

In terms of the classical theory in textbooks, the two components with phase separation in a binary polymer blend will, depending on their compatibility, have their respective Tg get closer or remain in their original values. According to the classical theory, the Tg of plastic component shall remain unchanged or move toward the lower Tg of rubber component in a rubber/plastic blend. However, ultra-fine full-vulcanized powdered rubber (UFPR) with a diameter of ca. 100 nm can simultaneously increase the toughness and the Tg of plastics, which is abnormal and is difficult to explain by classical theory. In this feature article, the abnormal behavior and its mechanism are discussed in detail.