基于苯乙烯/丙烯酸酯基硅油的高熔体强度聚丙烯的流变性能和发泡性能

摘要

High melt strength polypropylene(HMSPP) was prepared by melt grafting with styrene(St) and acrylic silicone oil(ASO) as grafting monomers and benzoyl peroxide(BPO) as initiator. The eff ects of St content on the rheology and foaming properties of isotactic polypropylene(iPP) were investigated. The FTIR results showed that St and ASO were grafted onto iPP. The rheological data of HMSPP,such as the obvious shear thinning in the low frequency of theη*-ω curves(η*:complex viscosity;ω:scanning frequency), deviating from the terminal in the low frequency of theG′-ω curves(G′:storage modulus),and obvious strain hardening of the extensional viscosity,proved that long branched chains had been added to the HMSPP molecules. When the addition of St and ASO were both 1.0%(w),the melt strength of HMSPP increased from 0.051 N to 0.770 N. Under this condition HMSPP exhibited excellent foaming properties,and its cell density increased to the maximum,from 7.0×106 to 1.3×108 cell/cm3.%以过氧化苯甲酰（BPO）为引发剂、苯乙烯（St）和丙烯酸酯基硅油（ASO）为接枝单体，制备无凝胶的高熔体强度聚丙烯（HMSPP），考察了St添加量对等规聚丙烯（iPP）流变性能和发泡性能的影响。FTIR表征结果显示，St和ASO成功接枝到iPP上。流变性能测试结果显示，HMSPP在η*～ω曲线（η*：复数黏度；ω：扫描频率）的低频区出现明显的剪切变稀现象，在G′～ω曲线（G′：储能模量）的低频区出现明显的偏离末端行为，在拉伸过程中拉伸黏度具有明显的应变硬化现象，说明HMSPP中有长支链结构存在。当St和ASO的添加量均为1.0%（w）时，HMSPP的熔体强度从0.051 N提高到0.770 N，且表现出优良的发泡性能，泡孔密度从7.0×106 cell/cm3提高到1.3×108 cell/cm3。