Crystallization, Melting Behavior, and Wettability of Poly(ε-caprolactone) and Poly(ε-caprolactone)/poly(N-vinylpyrrolidone) Blends

Both wettability and crystallizability control poly(epsilon-caprolactone)'s (PCL) further applications as biomaterial. The wettability is an important property that is governed by both chemical composition and surface structure. In this study, we prepared the PCL/poly(N-vinylpyrrolidone) (PVP) blends via successive in situ polymerization steps aiming for improving the wettability and decreasing crystallizability of PCL. The isothermal crystallization of PCL/PVP at different PVP concentrations was carried out. The equilibrium melting point (T-m(0)), crystallization rate, and the melting behavior after isothermal crystallization were investigated using differential scanning calorimetry (DSC). The Avrami equation was used to fit the isothermal crystallization. The DSC results showed that PVP had restraining effect on the crystallizability of PCL, and the crystallization rate of PCL decreased clearly with the increase of PVP content in the blends. The X-ray diffraction analysis (WAXD) results agreed with that. Water absorptivity and contact angle tests showed that the hydrophilic properties were improved with the increasing content of PVP in blends. The coefficient for the water diffusion into PCL/PVP blends showed to be non-Fickian in character. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2747-2755, 2010