Thermal decomposition of poly(vinyl chloride) and chlorinated poly(vinyl chloride). II. Organic analysis

Abstract

A concerted study of poly(vinyl chloride), chlorinated poly(vinyl chloride), and poly(vinylidene chloride) polymers by spectroscopy, thermal analysis, and pyrolysis‐gas chromatography resulted in a proposed mechanism for their thermal degradation. Polymer structure with respect to total chlorine content and position was determined, and the influence of these polymer units on certain of the decomposition parameters is presented. Distinguishing differences were obtained for the kinetics of decomposition, reactive macroradical intermediates, and pyrolysis product distributions for these systems. It was determined that chlorinated poly(vinyl chloride) systems with long‐chain CHCI units were more thermally stable than the unchlorinated precursor, exhibited increasing activation energy for the dehydrochlorination, and produced chlorine‐containing macroradical intermediates and chlorinated aromatic pyrolysis products. The poly(vinyl chloride) polymer was relatively less thermally stable, exhibited decreasing activation energy during dehydrochlorination, and produced polyenyl macro‐radical intermediates and aromatic pyrolysis products.

Electron spin resonance spectral study of PVC and XLPE insulation materials and their life time analysis

“…The major difference between the non-aged and aged spectral properties is the appearance of a singlet peak in the middle region in the graphs of the deteriorated samples. Similar ESR-pattern was reported during thermal degradation [16][17][18], photo degradation [19,20] or chemical dehydrochlorination [21] of PVC compound. It was also observed in the ␥-irradiated polyethylene compound sample by doses of several thousands megarads [22][23][24][25].…”

ESR Spectroscopy in Polymer Research

“…The formation of a si!1glet-line ESR spectrum was also observed during ther-ma1227, 882,1364,1365,1666,1680,1989) and phot01788, 2239, 2246, 2441) degradation, and chemical dehydrochlorination 562 ) of poly(vinyl chloride).…”

Thermal Decomposition Mechanism and Kinetics Study of Plastic Waste Chlorinated Polyvinyl Chloride

“…There are at least three different types of repeating units present in the polymer molecular structure: -CH 2 -CHCl-, -CHCl-CHCl-and a small amount of -CCl 2 -units [22]. Just as Liebman et al [39] explained, the greater stability of CPVC compared to that of PVC was due to long sequences of -CHCl-CHClunits in the polymer. Chlorination of PVC produces a change in the physical properties and thus improves the thermal properties of the polymer and makes it more stable [40], which is attributed in part to a crosslinking reaction and in part to elimination of reactive defects in the PVC structure [21], resulting in their difference in Stage I.…”