In Situ Polymerization of Titanium Isopropoxide in Polycaprolactone: Properties and Characterization of the Hybrid Nanocomposites

In this study, tetra isopropyl ortho titanate (TTIP) and polycaprolactone (PCL) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of novel nanocomposites by using an in situ sol-gel process. In addition, acrylic acid grafted polycaprolactone (PCL-g-AA) was investigated as an alternative to PCL. The hybrids (PCL/TiO2 and PCL-g-AA/TiO2) were characterized via Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical thermal analysis (DMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and Instron mechanical testing. It was found that the carboxylic acid groups of acrylic acid acted as coordination sites for the titania phase to form chemical bonds, thus improving the properties of the acrylic acid grafted composite compared with its acrylicacid-free counterpart. The TiO2 content also determined the strength of interfacial bonding between the polymer chains and the ceramic phase, as shown by changes in glass transition temperature (Tg) with TiO2 content. The maximum values of tensile strength and Tg were obtained with the PCL-g-AA/TiO2 composite at 10 wt % TiO2. At TiO2 contents above this, excess particles led to segregation between the organic and inorganic phases. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1749–1757, 2004