Miscibility and complexation behavior in poly(ethyl methacrylate)/poly(styrene‐co‐methacrylic acid), poly[2‐(N,N‐dimethylamino) ethyl methacrylate]/poly(styrene‐co‐methacrylic acid), and poly{styrene‐co‐[2‐(N,N‐dimethyl amino) ethyl methacrylate]}/poly(styrene‐co‐methacrylic acid) systems

Abstract

Abstract This contribution presents a study of the hydrogen‐bonding interactions between poly(styrene‐ co ‐methacrylic acid) containing 22 mol % methacrylic acid (SMA‐22) and poly(ethyl methacrylate) (PEMA), poly[2‐( N,N ‐dimethylamino) ethyl methacrylate] (PMAD), or poly{styrene‐ co ‐[2‐( N,N ‐dimethylamino) ethyl methacrylate]} containing 3, 12, or 21 mol % 2‐( N,N ‐dimethylamino) ethyl methacrylate (SMAD‐3, SMAD‐12, or SMAD‐21) by viscometry and differential scanning calorimetry (DSC). On the basis of the analysis of DSC thermograms and viscometric measurements, polymer miscibility was observed with the PEMA/SMA‐22 system. This miscibility was due to hydrogen‐bonding specific interactions between carbonyl groups of PEMA and carboxylic groups of SMA‐22. The SMAD‐3/SMA‐22 system was immiscible, whereas complexation was observed with PMAD/SMA‐22, SMAD‐21/SMA‐22, and SMAD‐12/SMA‐22 mixtures in butan‐2‐one. This complexation was due to stronger interactions between poly(styrene‐ co ‐methacrylic acid) and the 2‐( N,N ‐dimethylamino) ethyl methacrylate groups of PMAD or SMAD copolymers, as evidenced by viscometry and DSC. A similar phenomenon was observed for PMAD/SMA‐22 and SMAD‐21/SMA‐22 mixtures in tetrahydrofuran. For the SMAD‐12/SMA‐22 system in this solvent, such behavior was noted only in the presence of an excess of the copolymer SMAD‐12. This study showed that the minimum amount of interacting species required for the interpolymer complexation was higher in tetrahydrofuran than in butan‐2‐one. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 658–664, 2005