Journal of Polymer Science Part B: Polymer Physics, 2019, vol 57, 10, pp. 598-606
DOI:10.1002/polb.24816
Abstract
Many experimental results have revealed that the re-entanglement kinetics of disentangled polymers is much slower than that predicted by tube theory. This retarded recovery of fully entangled state is of practical significance that shear-induced modification may offer a way to improve processability for a polymer by reducing viscosity. This work tried to figure out the shear-rate dependence variation of viscosity in the view of evolution of entanglement state through disentanglement and re-entanglement, aiming to provide fundamental insights into application prospect of shear-induced modification in preparing “in-pellet” disentangled polymers prior to final processing. High-density polyethylene was sheared on a parallel-plate rotational rheometer with a linearly increased shear rate. Results showed that higher shear rate could induce further disentanglement, resulting in a lower viscosity with a reduction rate up to 93.7%, larger molecular weight between entanglements Me, and longer re-entanglement time. Additionally, less entanglement would give a larger lamellar thickness of sheared samples after nonisothermal crystallization. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 598–606
