Synthesis, structure and bioactivity of pHEMA/SiO2 hybrids derived through in situ sol–gel process

A novel procedure to synthesize poly(2- Hydroxyethylmethacrylate)-silica blend hybrids is presented. Methacrylate monomers bearing an alkoxysilyl unit, prepd. by Michael addn. of 2-Hydroxyethylmethacrylate (HEMA) to 3-Aminopropyltriethoxysilane (APTS), were employed. By 13C NMR and mass anal. it was possible to establish the formation of coupling hybrid species. A hybrid material, with final concn. of 30% wt./wt. of silica gel to the mass of polymer, was obtained through basic catalyzed sol-gel process of tetraethoxysilane (TEOS) and the alkoxysilyl unit of the hybrid monomer, followed by in situ free-radical polymn. Optical transparency and higher glass transition temp. than pHEMA suggest an increase in either d. or strong interphase interactions. Moreover, pHEMA/SiO2 gel blend hybrid exhibits better thermal stability than the as-prepd. polymer. Morphol. and structure were studied through SEM, transmission electron spectroscopy (TEM), and dynamic light scattering (DLS). The structure of the hybrid consisted of nanosilica, 10 nm in mean diam., uniformly dispersed in the pHEMA phase with strong interactions between the phases. Nevertheless, the swelling ratio of the hybrid was comparable to pHEMA. Using FT-IR spectroscopy, SEM and energy dispersive system (EDS), XRD anal. in vitro bioactivity of the hybrid, due to the inorg. phase, was ascertained therefore, the obtained hybrid can be used to make bioactive scaffold for bone engineering.