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

Full Paper: The formation of intermolecular hydrogen bonds in blends of nov olac 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 spec tra. The T-g and parameters of solid state C-13 NMR, such as the T-CH and s pin-lattice relaxation time in the rotating frame T-1p(H), indicate that th e London dispersion force (entropically favored) significantly affects the intermolecular hydrogen bonding of the blend. The phenoxy chain forces open ing of the intra-association of phenolic and thus creates more free OHs. Th is strong entropic effect reduces the total hydrogen bonding of the system especially when one of the polymer is the minor component. This also result s in the reduction of T-g and free volume expansion, reflecting in the incr ease of cross-polarization (C-H) time and molecular mobility within the phe nolic/phenoxy blend.