Inorganic-organic hybrids involving poly(ε-caprolactone) and silica network:: Hydrogen-bonding interactions and isothermal crystallization kinetics

Inorganic-organic hybrids mediated by hydrogen-bonding interactions involving silicon oxide network and poly(E-caprolactone) (PCL) were prepared via an in situ sol-gel process of tetraethoxysilane in the presence of PCL. Fourier transform infrared spectroscopy indicated that there were hydrogen-bonding interactions between carbonyls of PCL and silanol hydroxyls that were formed by incomplete poly-condensation in the sol-gel process. In terms of the frequency shift of the hydroxyl stretching vibration bands, it is concluded that the strength of the interassociation between PCL and silicon oxide networks is weaker than that of the self-association in the control silica network. The phenomenon of equilibrium melting point depression was observed for the PCL/silica system. The hybridization of PCL with silica network causes a considerable increase in the overall crystallization rate and dramatically influences the mechanism of nucleation and growth of the PCL crystallization. The analysis of isothermal crystallization kinetic data according to the Hoffman-Lauritzen theory shows that with increasing silica content in the hybrids, the surface energy of extremity surfaces increases dramatically for the hybrids. (c) 2005 Wiley Periodicals, Inc.