Author

Quan Sheng

Date of Award

4-1997

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Supervisor

Harald D. H. Stöver

Abstract

Novel procedures for the oxidation of 4-methylstyrene homopolymer and copolymers by a single step process have been developed. Poly(4-methylstyrene)s bearing a series of different functional groups (aldehyde, carboxylic acid, acetoxymethyl, nitrooxymethyl, trichloroacetoxymethyl, chloromethyl groups) have been prepared using these oxidation processes. As well, parameters that effect the reaction (molar ratio of oxidants to polymer, cosolvents, temperature, and reaction time) were investigated, and reaction mechanisms for these processes were proposed. A common feature of the oxidations is a reduction in molecular weight of the resulting polymers. Mechanisms of degradation of poly(4-methylstyrene) by ceric (IV) under oxygen or nitrogen were proposed. This backbone cleavage was minimized by forming copolymers of 4-methylstyrene and alkyl methacrylates (methyl methacrylate, n-butyl methacrylate, and dodecyl methacrylate) or of 4-methylstyrene/α-methylstyrene. These copolymers are resistant to oxidative backbone cleavage, due to the steric effect of the α-methyl comonomer. The degree of backbone cleavage depends on the α-methyl comonomer content and sequences in these copolymers. In addition, the thermal properties of functional polymers were studied by thermogravimetry and differential scanning calorimetry.

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