Thermodeformational behavior of microporous polyethylene films with different degrees of orientation

Microporous PE films were Prepared by melt extrusion, subsequent annealing, uniaxial tensile drawing, and thermal fixation, The effect of principal or ientational parameters associated with the development of porous structure (spin draw ratio, the tensile strain of the annealed samples,and strain rat e) on the thermo-deformational behavior of films was studied; the dependenc e of shrinkage on the temperature of thermal fixation was established. The samples with a higher draw ratio were shown to be characterized by a higher shrinkage as compared with the less oriented samples. The lower the strain rate of the annealed samples at the stage of pore formation, the higher th e shrinkage. The dependence of shrinkage on tensile strain epsilon passes a maximum at epsilon = 150%. As the temperature of the thermal fixation of t he samples is increased, shrinkage decreases.