Quantitative I.R.-messungen an p-substituierten polystyrolen

Abstract

Using the KBr disk technique we have measured the infra-red spectra of the poly( p-halogene styrenes), of poly( p-methyl styrene) and of poly( p-iso-propyl styrene). With all polymers, excepted the fluorine derivative, measurements were also made with CS 2 solutions. The absorptivities (ϵ max and ƒϵ dλ) of the following aromatic hydrogen vibrations were determined: out-of-plane vibration at about 830 cm −1, δ s (in-plane) at about 1010 cm −1, and δ as(in-plane) in the region between 1165 cm −1 and 1055 cm −1. In the case of δ s , ƒϵ dλ increases strongly from the fluorine derivative to the chlorine derivative; the absorptivities of δ as move in the opposite direction, the fluorine compound being an exception. As to the out-of-plane vibration, there are only slight differences. In the case of δ s and δ as , ƒϵ dλ and λ max depend on the molecular weight of the substituent in para position. The wave numbers of all aromatic hydrogen vibrations of the halogene derivatives increased from the iodine to the fluorine compound. Due to the non-ideal dispersion of the polymer in the KBr, ϵ max. (KBr) is always smaller than ϵ max (CS 2). The preparation technique described allows reproducible values for ϵ max (KBr). ƒϵ dλ depends little on the preparation technique. There is some evidence about an influence of the polar KBr on ϵ max.