The solid state C-13 NMR studies of intermolecular hydrogen bonding formation in a blend of phenolic resin and poly(hydroxyl ether) of bisphenol A

Abstract

Full Paper: The formation of intermolecular hydrogen bonds in blends of novolac type phenolic and poly(hydroxyl ether) of bisphenol A was investigated by studying its T-g behavior, excess volume, and solid state C-13 NMR spectra. The T-g and parameters of solid state C-13 NMR, such as the T-CH and spin-lattice relaxation time in the rotating frame T-1p(H), indicate that the London dispersion force (entropically favored) significantly affects the intermolecular hydrogen bonding of the blend. The phenoxy chain forces opening of the intra-association of phenolic and thus creates more free OHs. This strong entropic effect reduces the total hydrogen bonding of the system especially when one of the polymer is the minor component. This also results in the reduction of T-g and free volume expansion, reflecting in the increase of cross-polarization (C-H) time and molecular mobility within the phenolic/phenoxy blend.