聚氯乙烯的热可逆共价交联

利用环戊二烯 (CPD)在常温下自动二聚形成双环戊二烯 (DCPD)、在高温下DCPD又可解聚成CDD的热可逆Diels Alder反应 ,合成了DCPD二羧酸衍生物 ,并将其引作聚氯乙烯 (PVC)的共价交联 ,研究了交联剂种类和用量对交联程度、力学性能和流动特性的影响及交联产物的热可逆转化行为 ,制得了力学性能和耐热性均有所提高的热可逆共价交联PVC

A STUDY ON THERMALLY REVERSIBLE COVALENT CROSSLINKING OF POLYVINYL CHLORIDE

Based on the thermally reversible Diels\|Alder reaction between the cyclopentadiene and dicyclopentadiene,the dicyclopentadienyl dicarboxiate derivatives were synthesized by usual organic reaction,and it was taken into PVC molecular chain as a covalent crosslinking agent.The effects of crosslinking agent,catalyst and activator on the crosslinking rate,mechanical properties and the flow feacture of crosslinekd PVC were also investigated in detail.It has been found that when PVC was reacted with crosslinking agent in the melt directly,the crosslinking rate was low (crosslinking reaction taking place at 190℃ for 36min,the gel content of the system was only 26.3%),when the ammonium salt as catalyst and polyglycol as activator were added into the reactio system at a optimum ratio,the crosslinking rate can raise 7～9 times.The crosslinked PVC not only has good thermally conversion behavior through the analysis of reaction solubility,DSC and flow curves,but also exhibits flow behavior similar to uncrosslinked PVC.Based on the recipe of soft PVC,thermally reversible covalent crosslinked PVC with better mechanical properties in comparison with the original one was prepased.