On the mechanism of the formation of porous structure in filled polyethylene film by thermomechanical deformation

Abstract

AbstractThe pore‐formation mechanism in filled polyethylene film during the process of thermomechanical deformation has been studied. The film material consists of a high density polyethylene and SiO2. The rate of deformation as well as the initial thickness of the polyethylene film play a vital role in the formation of the porous structure. With an increase in the deformation rate, the contribution of crazes in the film decreases. Keeping all the parameters constant, with the increase in the initial film thickness, the porosity of the membranes decreases. The mechanism of pore formation is observed by scanning electron microscopy. It is established that the formation of crazes in the deformation process starts from the zones with lower adhesion of the filler with polymer and in the course of the process propagates throughout the mass. The final pore‐size distributions as well as the permeability data provide additional indirect evidence in favor of the observed mechanism.