Rheology And Crystallization Properties Of β Nucleating Agent Modified Of PPR

PP is excellent for its comprehensive performance, but some defects such as low impact strength, heatshrinkable etc, which limit the applications of PP. Improve comprehensive performance or certain aspectsperformance of PP through chemical or physical modification can expand the application range of PP.This paper research PPR which mixed with six kinds rare earth beta nucleating agent (WBG-1, WBG-2,WBG-3, WBG-4, WBG-5, WBG-6) respectively, and analyse the properties of mechanics, crystallization,rheology.By the research of mechanical properties of the PPR modified by the six nucleating agent, we found that:the sixβnucleating agent all can improve mechanics performance of PPR. Elongation of PPR modified byWBG-1(0.3%),WBG-2(0.1%) and WBG-6(0.1%) respectively increase from 256.3% to 945.4%, 747.1% and411.0%; PPR modified by WBG-3 and WBG-5 have good elongation both about 700% at anycontent(0.1%-0.5%); but the elongation is more than 700% when WBG-4 (0.1%-0.3%) mixed into PPR, alsothe impact strength at room(25oC) and low temperature(-30oC) increase. The section of PPR appears ductilefracture toughness nests obviously after mix a nucleating agent.Crystallization influences by the condition such as temperature, shear and thermal history besidesconcentration of nucleating agent, we studied the crystallization behaviour of PPR and its modified products.The results show that, pure PPR crystallizes slowly, the interface of sphaerocrystals is obvious, and thecrystallize rate of modified PPR was speed up, the size of sphaerocrystals was diminish, also it appears nointerface, form irregular "flower shape" crystal; modified PPR by WBG-1(0.3%),WBG-2(0.1%),WBG-3(0.1%) appeares two molten absorption peaks from DSC molten curves, and the ?βwas about 54.2%,50.6% and 45% respectively, and theβnucleation effect is better obviously; the Kx of modified PPR are about29.03% ,30% and 30% respectively by WAXD, and it's consistent with mechanical properties and DSCincome.The machining and extrusion rheological behaviour of PPR are influential by nucleating agent, weconduct a study of PPR modified by WBG-1βnucleating agent. The flow activation energy of PPR modifiedby 0.1%WBG-1 was large, shear stress has the trend to decrease with theβnucleating agent increase at thesame shear rate, shear viscosity decrease when mix into nucleating agent at the same low shear rate, but shearviscosity shows obvious draws close with the shear rate shifty when shear rate increases, the PO of PPR wasnot obvious with different nucleating agent; PPR appears small lose peak at 60℃-70℃by DMA, thedissipation factor of PPR modified by WBG-1 is increase to varying degrees.