Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Applied Science


William H Starnes, Jr


The purpose of this study was to elucidate the mechanisms of PVC fire retardance and smoke suppression induced by copper additives.;The experimental approaches involved: (1) the use of activated copper (Cu{dollar}\sp0{dollar}) to study PVC model-compound reactions and the crosslinking of PVC and (2) the pyrolysis of PVC model compounds in the presence of several copper additives in order to examine all of the possible chemical reactions involved in the formation of heavy products.;The results obtained from experiments with activated copper and allylic chloride model compounds suggest that the reductive coupling mechanism is a viable process in PVC. The Cu{dollar}\sp0{dollar} that caused the coupling was either (a) a slurry resulting from the reduction of CuI {dollar}\cdot{dollar} P(n-Bu){dollar}\sb3{dollar} with lithium naphthalenide or (b) a film created by the pyrolysis of copper(II) formate. Significantly, both the slurry and the film were also demonstrated to be capable of promoting the extensive crosslinking of PVC itself.;In small-scale sealed-ampule model compound pyrolysis experiments, several chemical reactions were revealed that may account for the crosslinking that occurs in copper-containing PVC. These reactions include Lewis-acid-catalyzed oligomerization and chloroalkylation, reductive coupling dimerization, alkene mono-halogenation (rechlorination), and aromatization.;For copper compounds, Lewis-acid catalysis is the major (if not the only) reaction pathway toward crosslinking; while in the case of high-purity copper metal, the reductive coupling mechanism apparently plays a major role in the crosslinking process.;Since the crosslinking of PVC is known to suppress the formation of the volatile aromatics whose combustion generates smoke, the results of this study indicate that copper-promoted Lewis-acid catalysis and reductive coupling dimerization will tend to prevent the evolution of smoke from the burning polymer.



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