INTERMACROMOLECULAR COMPLEXATION DUE TO SPECIFIC INTERACTIONS - 6 - MISCIBILITY AND COMPLEXATION BETWEEN POLY(STYRENE-CO-[P(2-HYDROXYPROPAN-2-YL)STYRENE]) AND POLY[N-BUTYL METHACRYLATE-CO-(4-VINYLPYRIDINE)]

In recent years, considerable attention has been focused on polymer mi scibility and complexation due to hydrogen bonding. Monodisperse, prot on-donating polystyrene (PS), that is, poly{styrene-co-[p- (2-hydroxyp ropan-2-yl) styrene]} [PS(t-OH)], was synthesized via chemical modific ation of polystyrene. Poly[n-butyl methacrylate-co-(4-vinylpyridine)] (BVPy), as a proton acceptor, was prepared by free-radical copolymeriz ation of the corresponding monomers at low conversion. In organic solu tions of PS(t-OH)/BVPy blends, viscometry was employed to study the co mplexation behavior. Solvents with different proton-accepting abilitie s were used and hence proved to exert distinctive effects on solution complexation. In very dilute solutions, the complex aggregate was obse rved by static and dynamic light scattering (LS). Differential scannin g calorimetry (DSC) investigation proved that miscibility could be gre atly enhanced when a small amount of hydrogen bonding was introduced i nto the originally immiscible PS/PBMA (polybutyl methacrylate) system. Although it was found that the T-g of the hydrogen-bonding polymer co mplexes occurred at higher temperatures with respect to linear weight- average value, DSC measurement alone could not accurately distinguish polymer complexes from ordinary miscible blends. Based on the data of miscibility from DSC and complexation from viscometry in 1,2-dichloroe thane for a few tens of blends, which cover broad ranges of the conten ts of interaction sites, a map showing the immiscibility-miscibility-c omplexation transitions by strengthening the hydrogen bonding for the system of PS(t-OH)/BVPy was successfully constructed.