Thermal behaviour of poly(methacrylic acid)/poly(N-vinyl-2-pyrrolidone) complexes

Poly(methacrylic acid)/poly(N-vinyl-2-pyrrolidone) (PMAA/PVP) complexes were prepared by two different procedures: simple mixing of preformed PMAA and PVP and radical polymerization of methacrylic acid in aqueous solution in the presence of poly(N-vinyl-2-pyrrolidone) (template polymerization). Differential scanning calorimetry, thermogravimetric analysis and Fourier-transform infrared spectroscopy were performed to evaluate the properties of the two kinds of complexes and to establish if they showed chemico-physical differences that could be related to the preparation procedure. The results of our investigation indicated that the behaviour of these complexes is qualitatively similar, although it was observed that in the case of the complexes produced by blending, the process of PMAA anhydridization induced by a programmed thermal treatment of the samples, was less favoured. This suggests that by template polymerization it is possible to prepare PMAA/PVP complexes having a more ordered structure than that of similar complexes produced by simple mixing of the preformed components.