Orientation in uniaxially drawn poly(ethylene terephthalate) (PET) film by two-dimensional C-13 nmr and FTir spectroscopy

Two-dimensional magic angle spinning (2D-MAS) C-13 n.m.r. spectroscopy and FTi.r. microscopy have been used to measure the orientation in uniaxially drawn film as a function of draw ratio. Results obtained agree well with those obtained by optical birefringence measurements. FTi.r. microscopy is a powerful method for mapping the orientation across the film thickness with quick data collection and analysis. The strength of the 2D-MAS n.m.r. method lies in its chemical and phase selectivity while its weakness lies in the time-consuming data acquisition and analysis coupled with the lack of knowledge about the orientation of the chemical shift tensor in the molecular frame. Copyright (C) 1996 Elsevier Science Ltd.