The mechanism of poly(vinyl chloride) stabilization by barium, cadmium, and zinc carboxylates. I. Infrared studies

Authors:
Publisher website
Google Scholar
Abstract
Deterioration in poly(vinyl chloride) is due primarily to zipperlike elimination of hydrogen chloride from the polymer chain, with formation of colored and easily oxidizable polyenes. Baum and Wartman have shown that elimination is initiated by rupture of certain particularly labile carbon‐chlorine bonds. The stability of poly(vinyl chloride) is enhanced by incorporation of various additives, among which are the barium, cadmium and zinc salts of certain carboxylic acids. To gain insight into the way these compounds retard deterioration, the infrared spectra of a series of poly(vinyl chloride) films, with and without admixed barium, cadmium, and zinc 2‐ethylhexanoate, were studied after various heat treatments. These studies have shown the presence of a band at 5.75 μ in the spectra of the films containing the 2‐ethylhexanoates which is absent from the spectra of the unmixed components. The intensity of the band varies with the particular salt, temperature, and duration of heat treatment. Absorption at 5.75 μ is attributed to the carbonyl stretching frequency of an aliphatic ester. The spectra of vinyl acetate–vinyl chloride copolymers show such bands. We propose that the stabilizing action of barium, cadmium, and zinc salts of carboxylic acids arises in part from esterifying displacements of labile chlorine atoms.

This publication has 3 references indexed in Scilit: