Some potential precursor routes to aromatic polyesters via quinone methides

Abstract

Poly(para-hydroxybenzoic acid) [pHBA] was discovered in the late 1950s and found to have chemical and mechanical properties which make it attractive for use as a high-performance polymer, potentially in engineering applications. However, the same properties make it difficult to fabricate into films or fibres. This thesis examines the philosophy of the precursor approach to intractable polymers as applied to the synthesis of aromatic polyesters generally and to pHBA specifically, by means of a review on the production of benzene derivatives by ring synthesis, and the polymerisation of 1,4-benzoquinone methides. Work undertaken includes the synthesis and characterisation of a precursor to 7,7-dichloro-1,4-benzoquinone methide, endo-cis-6-dichloromethylenetricyclo[6.2.1.0(^2,7)]undeca-4,9-dien-3-one, and the assignments of the (^1)H and (^13)C NMR spectra of endo-cis-6,6-dimethoxytricyclo- [6.2.1.0(^2,7)]undeca-4,9-dien-3-one (a correction to the published assignment) and its intramolecular 2+2 photocycloaddition product, 8,8-dimethoxypentacyclo- [8.1.0(^1,5).0(^2,9).0(^4,7).0(^6,10)]undecan-3-one.