Thermal analysis and phase behavior of poly(styrene-co-4-vinylpyridine)/poly(styrene-co-acrylic acid) mixtures

Due to the presence of specific interactions that occurred between poly(styrene-co-4-vinylpyridine) and poly(styrene-co-acrylic acid), novel materials as blends or interpolymer complexes of enhanced thermal stability were elaborated by simply mixing these copolymers and varying their initial blend composition in tetrahydrofuran or butan-2-one. The observed glass transition temperature-composition behaviors of miscible blends of these copolymers, cast from THF or interpolymer complexes obtained in butan-2-one, were analyzed according to Kwei and BCKV approaches that described well the experimental data of these systems, though better fits were obtained with the BCKV approach. A good fit of the S-shaped Tg-composition behavior, was obtained using Brostowʹs approach only. The presence of specific interactions within these materials was evidenced by FTIR spectroscopy. The thermal stability of all elaborated materials was analyzed by thermogravimetry.