INTERPOLYMER COMPLEXES AND MISCIBLE BLENDS OF POLY(N-VINYL-2-PYRROLIDONE) WITH NOVOLAC RESIN AND THE EFFECT OF CROSS-LINKING ON RELATED BEHAVIOR

The formation of complexes between poly(N-vinyl-2-pyrrolidone) (PVP) a nd novolac resin in various solvents was studied. Interpolymer complex es were formed in methanol, ethanol, 2-butanone, cyclohexanone and N,N -dimethylformamide (DMF). However, only polymer blends were obtained i n N-methyl-2-pyrrolidone. The nature of the solvent has a profound inf luence on the degree of interpolymer association. The formation of 1/1 and 2/1 ([novolac]/[PVP]) interpolymer complexes in DMF solution was shown by measurements of reduced viscosity, conductivity and clear poi nt. Differential scanning calorimetry revealed the single-phase nature of both the blends and the complexes of uncured novolac/PVP. The comp lexes had higher glass transition temperatures than those of the blend s with the same composition, and the strength of the interactions betw een the components in the complex is much higher than that in the blen d. The driving force in the formation of the interpolymer complexes be tween novolac and PVP is the hydrogen-bonding interaction between the hydroxyl of the novolac and the proton-accepting groups of PVP. Both t he blends and the complexes were cured with 15 wt% hexamethylenetetram ine relative to novolac content. The cured novolac/PVP blends were onl y partially miscible, but significant amounts of complex still existed in the cured complexes. Fourier transfer infrared spectroscopy reveal ed that the interaction between the components was rather strong for b oth the uncured and cured blends.