Interpolymer‐specific interactions and miscibility in poly(styrene‐co‐acrylic acid)/poly(styrene‐co‐N,N‐dimethylacrylamide) blends

Abstract

The miscibility or complexation of poly(styrene-co-acrylic acid) containing 27 mol % of acrylic acid (SAA-27) and poly(styrene-co-N,N-dimethylacrylamide) containing 17 or 32 mol % of N,N-dimethylacrylamide (SAD-17, SAD-32) or poly(N,N-dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glasstransition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan-2-one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA-27/SAD-32 and SAA-27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan-2-one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA-27/SAD-17 blends re-vealed that hydrogen bonding occurred between the hydroxyl groups of SAA-27 and the carbonyl amide of SAD-17. Quantitative analysis carried out in the 160-2108C temperature range for the SAA-27 copolymer and its blends of different ratios using the Painter-Coleman association model led to the estimation of the equilibrium constants K 2 , K A and the enthalpies of hydrogen bond formation. These blends are miscible even at 1808C as confirmed from the negative values of the total free energy of mixing DG M over the entire blend composition.

Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

“…The results obtained by DSC show, however, that these last blends were immiscible as the density of carboxylic groups in the PSMA copolymer increased. In previous studies, we confirmed by FTIR the presence of acid–acid dimers, and we calculated self‐association constants for styrene/methacrylic acid20 and styrene/acrylic acid25 copolymers containing increasing amounts of carboxylic groups. From a qualitative point of view, the PPO/PSMA blends were miscible only when the self‐association contribution was relatively low (due to the high PS dilution), which was overcome by the styrene/methacrylic acid repulsive interactions within the PSMA copolymers.…”

Interpolymer Complexes of Poly(N,N‐Dimethylacrylamide/Poly(Styrene‐co‐Acrylic Acid): Thermal Stability and FTIR Analysis

“…Indeed, the competition between polymer‐solvent and polymer‐polymer interactions governs the complex formation processes. SAA‐27 also formed soluble interpolymer complexes in THF and precipitate interpolymer complexes with SAD‐32 over the entire feed composition in butan‐2‐one 18…”

“…These copolymers were purified by repeated dissolution/precipitation in THF/methanol and to remove the residual solvent they were then dried to constant weight in a vacuum oven for several days at 60 °C. They were characterized as previously described18–20 by elemental analysis, UV spectroscopy and proton NMR. Their average molecular weights were examined by size exclusion chromatography using a Waters HPLC (elution with THF on cross‐linked polystyrene: rate 1 ml/min, calibration with polystyrene standards).…”

Phase Behavior and Thermal Analyses of Novel Blends Based on Poly(Styrene‐Co‐Itaconic Acid) and Poly(Ethylacrylate‐Co‐4‐Vinylpyridine)

“…Much research has been recently reported on interpolymer complexes formed by hydrogen bonding when polymers containing hydrogen bond‐donating groups are mixed with polymers containing hydrogen bond‐accepting groups in a common solvent . The nature of solvent plays an important role since complex formation may result in complexes of loose or ladder‐like structures.…”