苯乙烯接枝改性聚丙烯制备及其性能

Preparation and properties of polypropylene modified by grafting styrene

以过氧化苯甲酰为引发剂,采用反应挤出法将苯乙烯(St)接枝到等规聚丙烯(iPP)上,并考察了St浓度对接枝PP结晶性能、流变性能和发泡性能的影响。由FTIR、GPC和MFR表征结果表明St成功接到PP上;DSC结果表明,接枝PP结晶峰值温度与iPP相比最大提高了15.4℃;由剪切流变测试结果,在低频区,接枝PP的G′值增大,出现明显的剪切变稀现象,tanδ-ω曲线中出现平台,说明接枝PP中有长支链结构的存在;由于接枝PP的熔融流动速率降低即熔体强度提高,使得接枝PP的泡孔更规则。

With benzoyl peroxide as initiator,melt isotatic polypropylen(iPP)was grafted with styrene(St)by reactive extrusion process.The effects of St concentration on oscillatory shear rheology,foaming and thermal properties were comparatively evaluated.That Sts were grafted onto PP was comfirmed by FTIR,GPC and MFR.The results of DSC showed that the crystallization temperatures of grafted PPs were higher than that of iPP(maximum 15.4℃).The rheological characteristics of grafted PPs such as higher storage modulus(G′),the obvious shear thinning,aplateat in tanδ-ωplot at low frequency proved that the long chain branches have been added to the PP molecules.As the melt flow rate of grafted PP was reduced,i.e.the melt strength increased,the bubble pore of grafted PP was more regular than that of iPP.