Spin Orientation Measurement in Polyethylene Terephthalate

Abstract

Measurement of spin orientation in polyethylene terephthalate (PET) is discussed. The results from several techniques are compared and empirical correlations are presented between the different measures of spin orientation. The applica bility of the simple theory of rubber elasticity is considered and it is concluded that further work is needed to establish that PET, above the glass transition, obeys this theory. It is pointed out that spun PET probably cannot he considered as an amorphous polymer, since there is substantial evidence for the presence of order.