The effect of amines on the dehydrochlorination of poly(vinyl chloride)

Abstract

A study has been made of the effect of amines, particularly those used as catalysts in the preparation of polyurethane foams, on the dehydrochlorination of poly(viny1 chloride) (PVC). It has been shown that when PVC is heated at a temperature of 80°C in the presence of amines the levels of dehydrochlorination produced are considerably greater than those found if no amine is present. This has been attributed to a chemical dehydrochlorination reaction and could well have implications with respect to the physical and mechanical properties of the polymer for certain of its commercial applications.

Nitroxide-Mediated Polymerization of Vinyl Chloride at Low Temperature: Kinetic and Computational Studies

“…While dehydrochlorination of unstabilized PVC is well noted at high temperatures (> 150 °C),20 the conditions used in this polymerization are obviously much milder. However, it should be noted that amines can facilitate dehydrochlorination of PVC at lower temperatures (~80 °C),35 and so it is possible that the SG1 is selectively mediating the dehydrochlorination mechanism in the vicinity of the chain-end. In its favour, is the absence of competing reactions in the otherwise stable PVC-SG1.…”

The discoloration of vinyl instrument panels by polyurethane foam backing. II: Crosslinking of the vinyl resin

“…It has been suggested that the plasticizer loss seen in PVC/PUR systems is the result of crosslinking of the PVC to form an incompatible polymer system (5,6). The rate of plasticizer loss in all cases was constant throughout the 14 days in the oven.…”

“…The amine catalysts or other reactive species from the polyurethane catalyze the elimination of HC1 from the vinyl to form long, dark highly colored polyene sequences. This leads to the discoloration and has been speculated to lead to crosslinking of the vinyl, followed by loss of plasticizer because they are incompatible with the crosslinked polymer (5, 6).…”

Coarse-Grained Molecular Dynamics Modeling of Polyvinyl Chloride: Solvent Interactions, Mechanical Behavior, and Dehydrochlorination Effects

“…Supplemented by findings from Xu and colleagues, we acknowledge that upcycling processes typically encompass a series of chemical reactions under a range of temperatures and solvent conditions. Previous studies, − including experimental analyses of how different compounds, additives, and blends influence DHPVC, highlight the importance of its thermal and mechanical properties, notably in pyrolysis and the study of interfacial systems involving DHPVC . The insights obtained from this study are intended to help simulate and understand the thermophysical characteristics of PVC and DHPVC, as well as future studies of polymer blends.…”