Miscibility windows of poly(vinyl methyl ether) with modified phenoxy resin

Blends of poly(vinyl methyl ether) with partially methylated and benzoylate d poly(hydroxy ether of bisphenol A) (phenoxy resin, PH) have been studied. The optical appearance of the mixtures and their glass transition temperat ures as measured by differential scanning calorimeter has been used as macr oscopic criteria for miscibility. All miscible blends showed phase separati on (LCST) when increasing temperature as determined by optical microscopy. The PH degree of modification reduced the intrinsic miscibility of the blen ds as well as the values of the cloud point temperatures. This behaviour ha s been qualitatively discussed in terms of the reduction of the intermolecu lar strong interaction sites and its influence on the association equilibri a, which stabilise the blends. (C) 2001 Elsevier Science Ltd. All rights re served.