引发剂对聚丙烯熔融支化反应的影响

Influence of Initiator on Melt Branching Reaction of Polypropylene

利用转矩流变仪为反应器研究了聚丙烯的熔融支化反应,考察了3种不同引发剂种类及其用量对PP支化产物熔体特性的影响.结果表明：不同半衰期的引发剂对PP支化反应的影响不同,DCP和DHBP能更好地与体系中的自由基活性调控剂ZDMC配合,使反应过程更易调控;而BPO由于其半衰期较短,不适宜用于引发PP的熔融支化反应.引发剂过量会导致PP的降解,使PP的熔体流动速率升高,熔体强率降低,当DCP和DHBP的用量控制在0.05 ～0.15份的范围内时,产物的熔体强度较高,DCP以0.05份为宜,DHBP则选择0.1份.

A research on molten polypropylene＇ s branching reaction was implemented in a torque rheometer. One kind of modified polypropylene was fabricated, and its melt performances,related to the used three kinds of initiators＇ dosages and categories,were investigated at the same time. The results indicated that initiators with different half - lives made diverse influences on the branching reaction of PP. DCP and DHBP had a better synergy with ZDMC, used to control the radical activity,thus the reactive process could be regulated more easily. BPO was unfit for the branching reaction of PP as an initiator for its short half - life. A high initiator concentration could lead to PP＇ s degradation, thus making high MFR and low melt strength. Higher melt strength of PP would obtain when the contents of DCP or DHBP were limited in the range of 0.05 to 0.15 phr,and the best dosage of DCP and DHBP were 0.05 phr and 0.1 phr,respectivcly.