Summary: This contribution reports on a FT-IR study of the hydrogen bonding interactions within blends of different ratios of poly(styrene-co-methacrylic acid) containing 15 mol% of methacrylic acid PSMA-15 and poly(styrene-co-4-vinylpyridine) containing 15 mol% of 4-vinylpyridine PS4VP-15. Equilibrium constants describing both the self-association K 2 and inter-association K A in the (75:25) blend of poly-(styrene-co-methacrylic acid) containing 12 mol% of methacrylic acid PSMA-12 with poly(styrene-co-4-vinylpyridine) containing 22 mol% of 4-vinylpyridine PS4VP-22 were experimentally determined using a curve fitting analysis of the infra-red spectra. The FT-IR study at various temperatures confirms the miscibility of this blend up to 175 8C.
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 2108C. Two new bands characterizing these interactions appeared in the 1800-1550 cm -1 region at 1730 cm -1 and 1616 cm -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 2 and inter-association K 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 DG M . Optimization of the extent of intermolecular interactions between the two polymers in these blends is investigated.
Miscibility and strong specific interactions that occurred within homoblends of poly(styrene-co-4-vinylpyridine) containing 15 mol % of 4-vinylpyridine (PS4VP15) and poly(styrene-co-methacrylic acid) containing 15 mol % of methacrylic acid (PSMA15) have been examined by Fourier Transform infrared spectroscopy and DSC. The observed positive deviation of the glass transition temperature of the blends from the linear average line, was analyzed by the frequently used theoretical conventional approaches including the one very recently proposed by Brostow. A better fit was obtained when this latter is used. A reasonable agreement with experimental values was also obtained when the theoretical fitting parameter free method developed by Coleman, is applied to predict the composition dependence of the T g of this system. A thermodynamic analysis of hydrogen bonding in this system was carried using the Painter-Coleman association model and the variation of the Gibbs function of mixing and its different contributions and corresponding phase diagrams as a function of temperature and composition were estimated. This analysis predicted PSMA15 to be miscible with PS4VP15 in the whole composition range up to 150 C. Above this temperature, a partial miscibility is predicted when the PS4VP15 is in excess. The DSC results are in agreement with these predictions. V V C 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: [923][924][925][926][927][928][929][930][931] 2009
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