Deformation and annealing behavior. II. Thick polyethylene terephthalate films

Thick (5-30 mil) samples of polyethylene terephthalate (PET), drawn uniaxially and biaxially followed by thermal crystallization, were studied by replication electron microscopy and wide- and small-angle X-rays. Deformation of gold-decorated samples indicated that aggregates on the 200–500 Å scale move as units during deformation. Thermal crystallization of both uniaxially and biaxially drawn samples occurred with the formation of coarse 200–500 Å nodular aggregates, which, in turn, may consist of the 75–100 Å nodules observed by Yeh and Geil. At annealing temperatures above 180° C, fibrillar lamellae are formed, arranged perpendicular to the draw direction in uniaxially drawn samples and at random in biaxially drawn samples. Small-angle photographs and pole figures of uniaxially drawn and annealed samples can be explained in terms of a toroidal arrangement of poles centered about the draw direction.