PP/HDPE/EPDM三元共混物熔体的动态流变行为

Dynamic Rheological Behavior of PP/HDPE/EPDM Ternary Blends

用旋转流变仪测试了三元共混物PP EPS 30RA/HDPE 8916/EPDM和PP T30S/HDPE 5306/EPDM的动态流变行为,采用广义Maxwell模型对损耗模量-角频率曲线进行了拟合。结果表明,低频下,随着PP/HDPE质量比的增加,2种共混物的复数黏度逐渐增加,而储能模量值先增加后下降,最大值对应的PP/HDPE质量比为70/30。当PP EPS 30RA/HDPE 8916/EPDM三元共混物各组分质量比分别为30/70/3、50/50/3和70/30/3时,储能模量在低频下均出现第二平台,而PP T30S/HDPE 5306/EPDM共混物未出现该现象。在PP/HDPE/EPDM质量比达到50/50/3后,2种PP/HDPE/EPDM共混物的特征松弛时间逐渐变长。2种共混物的松弛模量-松弛时间曲线呈"扫把"状,模量高时松弛时间聚集,模量较低时松弛时间发散。

Dynamic rheological behavior was measured with rotational rheometer for two kinds of polypropylene( PP) /high density polyethylene( HDPE) /ethylene-propylene-diene-terpolymer rubber( EPDM) ternary blends( PP EPS 30 RA /HDPE 8916 /EPDM and PP T30 S /HDPE 5306 /EPDM),and the loss moduli( G″)-frequency( ω) data was fitted by the generalized Maxwell model. The results show at low ω,the complex viscosity of the two blends increases gradually with increase of PP /HDPE mass ratio,but the storage modulus first increases then drops,the maximum value arrived at PP /HDPE mass ratio of 70 /30. When the mass ratio of EPS 30 RA /HDPE 8916 /EPDM is 30 /70 /3,50 /50 /3 and 70 /30 /3,G″ at low ω reveals secondary plateau,while G″ of PP T30 S /HDPE 5306 /EPDM blends does not.When the mass ratio of PP /HDPE /EPDM is more than 50 /50 /3,the characteristic relaxation time of the two blends increases gradually. The relaxation modulus-relaxation time curves of the two blends present a shape of besom,the relaxation time gathered at high modulus,and diverged at low modulus.