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Solution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40 C. The hydrodynamic expansion factor, a h , and the unperturbed root mean square end-to-end distance, hr 2 i 1=2 h , found for the system indicated that the polymer coils contract as the temperature is raised. The long-range interaction parameter, B, was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, y, obtained from the temperature dependence of (1/2 À v) and the second virial coefficient, A 2 , are quite good in agreement with the calculated val-ues evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, v, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short-range, and long-range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems.

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Poly(maleic anhydride-alt-hexen-1)(poly(MA-alt-H-1)) has been synthesized by radical polymerization and characterized by DSC, FT-IR, acid number determination, viscometric and NMR methods. Data showed that the co-polymer is an alternating co-polymer whose composition does not depend on the monomer feed composition. Invertase was immobilized onto a poly(MA-alt-H-1) membrane via glutaraldehyde and bovine serum albumin. The Km value of poly(MA-alt-H-1)-invertase was approximately 4.4-fold higher than the free enzyme, indicating decreased affinity by the invertase for its substrate (sucrose), whereas Vmax was lower for the immobilized invertase. Immobilization improved the pH stability of the enzyme, as well as its temperature stability. Immobilized samples obtained were stable and could be used many times over a period of 2 months without considerable activity loss.