Effect of Annealing on the Porous Structure Formed upon Deformation of PET in a Liquid Medium

Abstract— The effect of annealing on the porous structure formed upon deformation of poly(ethylene terephthalate) (PET) in a physically active liquid medium has been studied by means of small-angle X-ray scattering. Isometric annealing of the crazed polymer at temperatures below T_g has been ccompanied by decrease in specific surface area of the fibrils connecting the walls of the crazes, the bulk porosity remaining unchanged. During PET annealing at temperatures exceeding T_g, reduction in the dispersion of the fibrillated material of crazes has been accompanied by decrease in the volume of microvoids, more pronounced at higher treatment temperature. The obtained results have been analyzed from the point of view of changes in the structure of crazes during annealing.