Molecular orientation behaviour of uniaxially stretched poly(vinyl chloride) film: 2. The fourth moment of molecular orientation measured by the polarized fluorescence method

Abstract

In order to measure the fourth moment of molecular orientation of poly(vinyl chloride) film a new polarized fluorescent method is examined. The fundamental principle of the method is to employ the polyene and the carbonyl radicals formed in the molecular chain, at the working process or with heat treatment, instead of a fluorescent dyestuff. It is necessary, in this method, to estimate the ratio of polyene to carbonyl in the sample, and the value is found to be 1.5 for unheat treated PVC film or 1.0 for heat treated PVC film. The second moment 〈cos 2ϑ〉 and the fourth moment 〈cos 4ϑ〉 are evaluated from the fluorescence intensity pattern. The applicability of this method is verified by comparison with the second moment derived from the birefringence. Dependence of deformation mechanism on draw temperature and plasticizer content are also investigated on the basis of a structural model composed of the characterized molecular chain, the practicability of which was already established by observations of the change in birefringence with draw ratio.