Blends of poly(hydroxypropyl methacrylate) with 4-vinyl-co-N-vinyl-2-pyrrolidone and with vinyltrimethylsilane-co-n-vinyl-2-pyrrolidone copolymers. The effect of copolymer composition on interpolymer compatibility

Glass transition temperatures (Figs. 1, 3), DSC and TGA thermograms (Figs. 2, 4), and Fourier transform infrared (FTIR) spectra (Fig. 5) showed the binary blends (Table 1) of poly(2-hydroxypropyl methacrylate) (PHPMA) with 4-vinylpyridine-co-N-vinyl-2-pyrrolidone (4-VPy-co-VP) to be compatible over the whole range of compositions. The blends of PHPMA with vinyltrimethylsilane-co-N-vinyl-2-pyrrolidone (VTMS-co-VP) were found to be compatible up to VTMS contents of ∼ 25 wt.%. The former blends (Figs. 1, 2) are believed to be compatible on account of H-bonding of PHPMA's OH with the 4VPy and VP units of 4VPy-co-VP. In the latter blends, up to 25.7% of VTMS, H-bonds between PHPMA's OH groups and VP units suffice to provide compatibility, but at >25.7 wt. % VTMS, hydrophobic interactions of the VTMS moieties prevail and phase separation occurs.