SURFACE STUDIES OF STEREOREGULAR POLY(METHYL METHACRYLATE)S - EFFECT OF INTERFACE ON NEAR-SURFACE COMPOSITION AND CRYSTALLINITY

The surface microstructure of the cast films of syndiotactic and stere ocomplex poly(methyl methacrylate)s (PMMA) was studied by the attenuat ed total reflection IR (IR/ATR) method. For comparison, the bulk struc ture was analyzed by transmission IR spectroscopy. For the syndiotacti c PMMA, the relative intensity of the ''crystalline'' band at 860 cm(- 1) to the ''amorphous'' band at 841 cm(-1) in the IR/ATR spectra indic ates that the degree of crystallinity is enhanced or reduced near the surface region, depending on the degree of polymer stereoregularity an d the contacting medium. For a stereocomplex PMMA film it was found th at the surface regions are less crystalline than the bulk of the film. The relative intensity of the peak at 750 cm(-1) to that at 758 cm(-1 ) in the IR spectra also indicates that the stereocomplex film contain s an excess of the syndiotactic component in the surfaces and that the surface enrichment is stronger at the air-side surface.