Synthesis and characterization of poly(arylene ethers) and functionalized oligomers

Abstract

Molecular weight control and endgroup functionalization in poly(arylene ether sulfones) has been achieved by two synthetic routes. The first utilizes DMSO/sodium hydroxide and aminophenol to introduce the amine functionality. This route, though synthetically useful, suffers from serious limitations, such as hydrolytic side reactions and oxidation of the end capping reagent. An alternative route utilized K₂CO₃/NMP as base and solvent respectively. This approach has been used with great success in the preparation of both high molecular weight polymers and functionalized oligomers. We have extended this method to include amine terminated oligomers through the use of a novel aminophenolic compound 2-p-aminophenyl-2-p-hydroxyphenylpropane or MBA. The use of MBA to introduce terminal amine functionality allowed a simpler, 1-step synthesis of controlled molecular weight oligomers to be realized. Our investigations focused on bisphenol-A based systems, but this technique may be also utilized with other bisphenols.

The synthesis and characterization of a wide variety of derivatives of these functionally terminated oligomers was demonstrated. A number of potential post reactions involving these oligomeric diamines were investigated and synthetic techniques to prepare novel block and segmented copolymers were defined. As the molecular weight of the sulfone oligomer was varied, the percent sulfone character in a given polymeric material could be systematically changed. The effect was studied in block copolymers with poly(arnide sulfones) and in novel modified epoxy and bismaleimide thermosetting systems.