Interpolymer association between poly(vinylpyridines) and poly(mono-n-alkyl itaconates). Effect of the n-alkyl substituent

The binary polymeric systems formed by some poly(mono-n-alkyl itaconates) and poly(2-vinylpyridine) or poly(4-vinylpyridine) are studied. Depending on the solvent, two different types of material have been synthesized. On the one hand, using methanol as common solvent, we have obtained solid polymer-polymer complexes the composition of which is determined by the initial mixing conditions. On the other hand, pyridine avoids the complexation process, allowing to obtain a true solution of both polymers and, therefore, a solid polymer blend of known composition by solvent casting. Yields of the complexation and stoichiometries of the polymer-polymer complexes have been analysed. In this way, a favoured composition in the range from 3:2 to 1:1 for the mole ratio (referring to repeating units) ratio poly(mono-n-alkyl itaconate): poly(vinylpyridine) was observed depending on the poly-(mono-n-alkyl itaconate used). Differential Scanning Calorimetry and thermogravimetry have been employed to study the thermal behaviour of complexes and blends. Viscometry measurements have been performed to analyse the interactions in solution. One of the aims of this work has been to analyse the effect of the side group of the poly-(mono-n-alkyl itaconate) in the mixing process as well as in the characteristics of the final products. In this way, higher complexation yields have been obtained using poly-(mono-n-alkyl itaconates) with longer n-alkyl side groups due to the additional stabilisation by solvophobic interactions. On the other hand, the poly(mono-n-alkyl itaconates) with longer n-alkyl groups form polymer-polymer complexes with a higher proportion of poly(4-vinylpyridine), presumably due to their slower kinetics of complexation.