ИСТИНА

The mechanical behavior of the rolled PET filmes at high tensile speed has been studied. Upon high speed streting the heating of unrolled PET is accompanied by the appearance of pores, reduction in the stretсhing stress, increase in the degree of stretching in the neck, and its astable propagation, As the degree of rolling increases the minimum on the speed dependence of the lower yield point disappear. The rolling reduces the degree of deformation localisation in the neck and reduces polymer heating. Despite the heating the rolling completely supress the pore formation. The mechanism of descibed phenomens is suggest.