Comparison of the Rheological Behavior of Iso- and Syndiotactic Polypropylenes

The rheological behavior of iso- and syndiotactic polypropylenes (iPP sPP) for two different temperatures 175 190˚C at atmospheric pressure is analyzed employing the Yahsi-Dinc-Tav (YDT) non-Newtonian viscosity model. predicted with shear rates 0.093 to 93.91 s-1 on PPs compared corresponding estimations from Cross-like obtained results YDT model deviate reported experimental observations 1.041 iPP 1.86 sPP. From zero correlation temperature- vacancy fraction- dependent thermo-occupancy function, Yh = Yh(h, T), parameters were ascertained associated polymer tacticity. relation, an increase in T) function hole fraction loss increased viscosity. dependence derivative logarithm (viscoholibility) fraction, as a temperature, h=h(P,T), procured Simha-Somcynsky theory displays exponentially decreasing behavior.