Direct grafting of ε-caprolactone on solid core/mesoporous shell silica spheres by surface-initiated ring-opening polymerization

Poly(epsilon-caprolactone) (PCL) was formed on Solid core/mesoporous shell (SCMS) silica surface by surface-initiated ring-opening polymerization (SI-ROP). The SI-ROP of F-caprolactone was achieved by heating a mixture of SCMS silica, c-caprolactone and the tin(II) 2-ethylhexanoate [Sn(Oct)(2)] in a anhydrous toluene for 20 h at different temperatures viz. 40, 60, and 80 degrees C. The PCL grafted SCMS silica was characterized by fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray, differential scanning calorimetry and scanning electron microscopy (SEM). The FTIR spectroscopic analysis reveals the formation of ester linkage between PCL and hydroxyl terminated SCMS silica. TGA investigation shows increase in PCL content on SCMS silica surface with increase in reaction temperature. The SEM photographs clearly show the formation of PCL polymer on the SCMS silica surface without altering the spherical nature of SCMS silica. (c) 2007 Wiley Periodicals, Inc.