Dr Sho-Cong Dai
Telephone: 93517151, email: scdai@mech.eng.usyd.edu.au
Investigation of Elongation and Shear Induced Crystallization of Polypropylene
Abstract: The flow fields such as elongation and shear introduce different degrees of anisotropy to the polymer melt, which modify the nucleation and crystallization behavior. In this project, the rheology and structure formation of polypropylene have been studied under elongational and shear flow in polymer melts. Rheometry testing and DSC measurements of polypropylene have been carried out. For elongational experiment, the effect of crystallinity on elongational load is obvious. In isothermal crystallization of the PP, it was found that there was a transition point at which the load started increasing abruptly but the measured crystallinity and diameter did not change abruptly. It indicated that the microstructures had a critical change or rearrangement at the transition point, which was found in the sheared samples that experienced a viscosity transition. The experimental data shows that shear and elongational viscosities are affected by deformation rates, temperature, time, cooling rate, crystal growth and structure formation.
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 | Constitutive Modelling for Polymer Processing |
