Design and development of mesoporous silica reinforced skeletal modified triaryl pyridine core based polybenzoxazine (SBA-15/PBZ) nanocomposites

A new series of novel mesoporous silica filled polybenzoxazine (SBA-15/PBZ) nanocomposites were designed and developed. Mesoporous SBA-15 was first functionalized using 3-mercaptopropyltrimethoxysilane (MPTMS). The thiol functionalized mesoporous SH-SBA-15 was then characterized by FT-IR, TGA and TEM analyses. Three different types of maleimido terminal triaryl pyridine core benzoxazines were prepared and confirmed by NMR and FT-IR techniques. Varying weight percentages (1, 3, 7, 5 and 10 wt %) of thiol functionalized mesoporous silica (SH-SBA-15) were then reinforced into maleimido terminal benzoxazine matrices to prepare SBA-15/PBZ nanocomposites. The successive increments in the weight percentages of SH-SBA-15 into the polybenzoxazine matrices exhibited lower values of the dielectric constant, superior thermal stability and higher glass transition temperature than those of neat PBZs. The developed nanocomposites were also found to have better flame retardancy and low water uptake percentage. The optical properties were ascertained by the UV–vis absorption bands in the region of 200–400 nm and strong fluorescence emissions were also observed in the wavelength range of 300–550 nm through photoluminescence analysis. The mesoporous nature of the SBA-15 after incorporating in the PBZ matrices was retained and which was evidenced by SEM and TEM images.