Blending properties of poly(vinyl alcohol) and nylon 6-clay nanocomposite blends

An investigation of the blending, rheological and tensile properties of poly(vinyl alcohol) (PVA) and nylon 6 clay (NYC) nanocomposite blends was conducted. The characteristics of melting endotherm, X-ray diffraction patterns of alpha form PVA crystals and hydrogen-bonded hydroxyl groups originally associated with the PVA resin almost disappear after blending less than 16.7 wt% of PVA in NYC resins. However, the characteristics of melting endotherm, X-ray diffraction of alpha form PVA crystals and hydrogen-bonded hydroxyl groups originally associated with the PVA resins appear gradually as the PVA contents of NYC/PVA specimens are more than 16.7 wt%. The torques vs. time measurements and tensile properties of NYC/PVA specimens support the ideas that PVA molecules are miscible with PA molecules to some extents in the molecular level as the PVA contents of NYC/PVA specimens are less than 16.7 wt%. Moreover, the additional demarcated humps and significantly increased torques and "stabilized" time values support the presence of separated PVA phases in NYC/PVA specimens as their PVA contents are more than 50 wt%. On the other hand, the alpha form PA crystals continue to grow at the expense of gamma form PA crystals as the PVA contents of NYC/PVA specimens increase, and the characteristics of the gamma form PA crystals originally shown on the melting endotherm and X-ray diffraction patterns of the NYC resin can barely be seen as the PVA contents of NYC/PVA specimens are equal to or more than 50 wt%. Possible reasons accounting for these interesting blending properties are proposed.