Fabrication of highly durable hydrophobic PBZ/SiO2 surfaces

Abstract

The structure of the synthesized precursors [4-phenyl(diazenyl)phenol (PAP)] & [N,N′-bis(4-aminophenyl)terephthalamide (APTA)] and benzoxazine monomer [bis(6-phenyl diazenyl-3,4-dihydro-2H-1,3-benzoxazinyl)terephthalamide (BZO-TA)] were confirmed by Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (¹H & ¹³C-NMR) spectroscopy. The miscibility and curing behaviour of the SiO₂ nanoparticles with benzoxazine was examined by Differential Scanning Calorimetric (DSC) analysis. Polybenzoxazine–silica nano hybrids [PBZ:SiO₂] with different weight ratios of SiO₂ nanoparticles (1, 3 and 5 wt%) were prepared by a thermal curing method. Surface morphological studies from SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy) revealed that the PBZ:SiO₂ hybrids with same compositions show hierarchically structured roughness. FT-IR was used to investigate the thermal-curing reactions and hydrogen bonding interactions in both polybenzoxazine and its hybrids. Contact angle analysis indicated that the hybrids have a hydrophobic nature and low wettability. The thermal and mechanical stabilities of the hybrids were studied using Thermogravimetric (TGA) and Dynamic Mechanical Analysis (DMA).