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Quantitative evaluation of hydrogen bonding of poly(4-vinyl phenol)/poly(ethylene oxide) PVPh/PEO blends was conducted using Fourier transform near infrared (FT-NIR) spectroscopy. Absorption coefficients of the free (a F ), intra-(PVPh-PVPh) (a A ) and inter-associated (PVPh-PEO) hydroxyl groups (a I ) were estimated. Two sets of approximations were tested, including adopting a least-squares refinement method to calculate absorption coefficients from all NIR spectra or using a literature value for a F . Each set of absorption coefficients thus estimated were used to determine hydroxyl concentration for the free and hydrogen-bonded hydroxyl overtone bands in the blends. A comparison is made among the resultant concentrations of the free, intra-and inter-associated hydroxyl groups. The concentration of free hydroxyl groups markedly decreases with PEO percentage, and that of intra-associated hydroxyl remains almost constant. Concentration for the inter-associated hydroxyl groups in the blends increases very slowly above 0.2 PEO weight fraction. When concentration of OH groups is reported per PVPh chain, FT-NIR measurements show a broad maximum in the number of interchain hydrogen bonds. This result can be used to explain partially previous orientation behaviour observed for PVPh/PEO blends.

ABSTRACT:The component dynamics and molecular parameters were investigated for miscible poly(4-vinyl phenol)/poly(ethylene oxide) (PVPh/PEO) blends. Global values of molecular weight between entanglements (M e ) were first estimated for the blends and were compared with existing athermal model predictions. Global interchain friction coefficients () of the blends were deduced from the zeroshear viscosity. A maximum was observed at a composition of 20 -30 wt % of PEO. Chain dimensions of this phase are estimated by using a relationship between the plateau modulus and a packing length (i.e., number of individual chains present in a given small volume of the melt). A slight increase in M e is observed at low PEO weight fraction (before 0.20), followed by a sharp decrease in M e values after this concentration. Values of in PVPh/PEO blends show a maximum value at 20 -30 wt % of PEO.

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