Adamantyl-substituted phenolic polymers

Abstract

4-(1-Adamantyl)phenol was synthesized via Friedel-Crafts reaction of 1-bromoadamantane and phenol. Substitution in the phenol para position forces polymerization to occur only in the ortho positions to give a linear polymer. Variations in formaldehyde amount, reaction time, and catalyst were evaluated. Increasing the amount of paraformaldehyde increased formation of cyclic octamer, an easily identified by-product due to its insolubility in common organic solvents. The cyclic octamer was acetylated to give a soluble model compound for comparison to acetylated polymers by IR and NMR. All of the synthetic variations employed produced low molecular weight polymers as indicated by NMR end-group analysis and SEC. The polymers showed number-average molecular weights of ca. 3000 (versus polystyrene standards by SEC), and exhibited glass transition temperatures ranging from 175–230°C, an increase of ca. 100°C over unsubstituted and para-alkyl substituted analogs. All of the samples exhibited a 10% weight loss at 400°C in nitrogen, indicating thermal stability much greater than the parent and alkyl-substituted polymers. © 1996 John Wiley & Sons, Inc.