MORPHOLOGY AND PHASE-BEHAVIOR OF POLY(METHYL METHACRYLATE) POLY(STYRENE-CO-ACRYLONITRILE) BLENDS MONITORED BY FTIR MICROSCOPY/

It has been shown that Fourier transform infrared (FTi.r.) microscopy is able to monitor the phase morphology in blends of poly(methyl metha crylate) and poly(styrene-co-acrylonitrile). This is carried out by th e spatially resolved detection of the absorbances of the C=O stretchin g vibration of the ester group of poly(methyl methacrylate) at 1732 cm (-1) and the C=N stretching vibration of poly(styrene-co-acrylonitrile ) at 2238 cm(-1). The most serious restriction for FTi.r. microscopy i s the large i.r. spot size which limits the spatial resolution of the detectable morphologies. An enormous advantage of FTi.r. microscopy co mpared to optical microscopy is its ability to provide quantitative in formation on the chemical composition of the phases. These data taken at different annealing temperatures can be used to obtain the phase di agram of blends showing lower critical solution temperature behaviour. Larger deviations of data points measured by FTi.r. microscopy compar ed to cloud point measurements are observed at the poly(methyl methacr ylate)-rich side of the phase diagram, where also the error of the FTi .r. microscopic determination of the phase composition is larger for t he blend system under investigation. (C) 1997 Elsevier Science Ltd.