Coating Kinetics of Fluoropolymer Process Aids for Sharkskin Elimination: The Role of Domain Size
D Bigio, Mathurin G. Meillon, S B. Kharchenko, David C. Morgan, Hui Zhou, S Oriani, C Macosko, Kalman D. Migler
We study the ability of fluoropolymer based polymer processing aids (PPA) to eliminate surface melt fracture (sharkskin) during extrusion of polyethylene in relation to blend morphology (PPA droplet size) and processing conditions (shear rate). Under the conditions of a constant throughput we simultaneously monitor the die entrance pressure, the PPA coating thickness and the degree of fracture. The thickness of the fluoropolymer coating on the die surface is measured in-situ through frustrated total internal reflection. We find a substantial enhancement in the coating rate and the magnitude of the steady state coating thickness as well as the faster elimination of sharkskin upon increase of PPA droplet size. These results are consistent with recently developed models of the coating process.
, Meillon, M.
, Kharchenko, S.
, Morgan, D.
, Zhou, H.
, Oriani, S.
, Macosko, C.
and Migler, K.
Coating Kinetics of Fluoropolymer Process Aids for Sharkskin Elimination: The Role of Domain Size, Journal of Non-Newtonian Fluid Mechanics
(Accessed January 19, 2022)