MAH接枝LDPE对PET/LDPE共混物增容作用的研究

本文研究了马来酸酐(MAH)在引发剂过氧化二异丙苯(DCP)存在下,与LDPE在挤出机中进行熔融接枝反应,所得接枝物GPE对PET/LDPE共混体系的增容作用.共混物的冲击强度及应力应变曲线结果表明.GPE能明显改善共混体系的相容性,提高共混体系的冲击强度,仅用20%的GPE就能使共混物由脆性断裂变为韧性断裂.利用SEM观察共混物的冲击断面形貌,结果表明,PET与LDPE完全不相容,GPE能明显改善PET与LDPE共混物的相容性,使分散相颗粒细化.而DSC结果表明:PET/LDPE/GPE与PET/LDPE一样都是热力学不相容体系,共混物存在两相结构,PET与LDPE不形成共晶.GPE在共混物中仅起相间界面相容剂的作用.

A Study of the Effect of MAH Graft LDPE on the Compatibility of PET/LDPE Blend

The effect of MAH graft LDPE,which was melting-grafted from MAH and LDPE in the presence of initiatior DCP in extruder,on the compatibility of PET/LDPE blend was studied in this paper. The impact strength and stress-strain curves of the blend showed the compatibility of the blend could be modified by GPE,and the impact strength of the blend could also be improbved as well. Only 20% of GPE could make the blend from brittle fracture transmute to tough fracture. The result of an observation of the impact section of the blend by SEM showed PET was incompatible with LDPE,but the compatibility of PET with LDPE could be improved by GPE, making the dispersion particle more fine. The result of DSC showed both PET/LDPE/GPE and PET/LDPE were thermodynamic incompatible systems, there were two phases in the blends, but no cocrystal of PET and LDPE and LDPE. GPE was only a compatibilizer for phase interfaces.