Phthalide cardo chain extended imine skeletal linked maleimido end capped nanotitania reinforced novel polybenzoxazine (nTiO 2 /PBZ) hybrid nanocomposites

Abstract

A new class of nanotitania reinforced polybenzoxazine (nTiO₂/PBZ) hybrid nanocomposites was synthesized using newly designed phthalide cardo chain extended imine skeletal linked maleimido end capped polybenzoxazine (PHM-PBZ) and nTiO₂ through in-situ sol-gel method. The formation of hybrid nanocomposites was confirmed by NMR and FT-IR spectra. The structurally stable nTiO₂ present in the nTiO₂/PBZ hybrids accounted their exceptional thermal stability and good char yield. The restricted motion of flexible polymeric chain resulted from the inclusion of nTiO₂ in the PBZ system increased the glass transition temperature (T _g ) to a higher percentage than that of neat PBZ system. With the successive enhancement in the incorporation of nTiO_2, the synthesized nanocomposites exhibited better thermal stability, higher flame retardancy and lesser water absorption behaviour than the of neat PBZ. The sequential increments in the loading level of nTiO₂ onto the PBZ matrices caused the lower value of dielectric constant than that of neat PBZ. The homogeneity and successful dispersion of the nTiO₂ fillers in the PBZ matrix were ascertained from the strong fluorescent emissions observed in the wavelength range of 300–550 nm through optical studies. Scanning electron microscope and transmission electron microscopic micrographs evidenced the successful incorporation of nTiO₂ as can be seen from the different morphology at the nanoscale level in the PBZ matrix. This kind of structurally designed nTiO₂/PBZ nanocomposites may find multifaceted applications in the form of adhesives, encapsulants, matrices and sealants and in the fields of automobile and microelectronics applications for better performance and longevity.