Thermodynamic Hydrogen Bonding in Poly(styrene-co-acrylic acid)/poly(styrene-co-4-N,N-dimethylacrylamide) Blends

• Published in: Polymer engineering and science 2008-03, Vol.48 (3), p.458-466
• Main Authors: ELMILOUDI, K, HADJ HAMOU, A. S, DJADOUN, S
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Hydrogen bonds; Organic polymers; Physicochemistry of polymers; Polymer blends; Polystyrene; Properties and characterization; Structure, morphology and analysis; Thermodynamics
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.20978

FTIR study of the hydrogen bonding interactions within blends of different ratios of poly(styrene-co-acrylic acid) containing 18, 27, and 32 mol% of acrylic acid (SAA) and poly(styrene-co-N,N-dimethylacrylamide) containing 17 mol% of N,N-dimethylacrylamide (SAD-17) was carried out qualitatively and quantitatively in the temperature range varying from room temperature to 210°C. Two new bands characterizing these interactions appeared in the 1800-1550 cm^sup -1^ region at 1730 cm^sup -1^ and 1616 cm^sup -1^ and are attributed to "liberated" carbonyl group of the acidic copolymer and the "associated amide" carbonyl group, respectively. Equilibrium constants describing both the self-association K^sub 2^ and inter-association K^sub A^ and the enthalpy of hydrogen bonding formation in the different blends were experimentally determined using a curve fitting analysis of the infra-red spectra as a function of temperature using the appropriate equations derived from the Painter-Coleman association model. The obtained results confirm the miscibility of these blends in the considered temperature range from the negative values of the total free energy of mixing ΔG^sub M^. Optimization of the extent of intermolecular interactions between the two polymers in these blends is investigated. [PUBLICATION ABSTRACT]