高熔体强度聚丙烯树脂的结构与性能

采用差示扫描量热法、傅里叶变换红外光谱、毛细管流变、熔体拉伸等方法,从结晶性、黏弹性及物理机械性能等方面对高熔体强度聚丙烯(HMSPP)树脂进行结构表征与性能分析。结果表明:HMSPP树脂具备较高的弯曲模量,同时具备优异的抗熔垂能力和更宽的加工温度;拉伸黏度随拉伸速率的增大而增大,呈现出HMSPP应变硬化这一明显行为,使得熔体在热成型过程中具有均匀变形的自我调节能力,从而克服普通聚丙烯在热成型加工中的严重熔垂问题;含有较长接枝链段的HMSPP树脂在刚性、熔体强度、结晶性能等方面均优于普通聚丙烯。

Structure and properties of high melt strength polypropylene resin

The structural characterization and property analysis for high melt strength polypropylene(HMSPP)resins were conducted by means of differential scanning calorimetry(DSC),Fourier transform infrared spectroscopy (FTIR),capillary rheology and melt tension in accordance with crystallinity,viscoelasticity and physico-mechanical properties,etc.The results indicate that the HMSPP resins have excellent sag resistance and wider range of processing temperature besides its higher flexural modulus.The tensile viscosity of the resins increases with the tensile rate,and the HMSPP melt presents obvious behavior of strain hardening.These features of the HMSPP resins endow the resin melt with self-adjusting ability for homogeneous deformation during thermal forming,thereby avoiding the serious sag the conventional polypropylene usually suffer in the process of thermal forming.Moreover,the HMSPP resins with longer graft chain segments have the advantages over conventional polypropylene in the aspect of rigidity,melt strength and crystallinity.