Synthesis of three novel silane-based carboxylic acids for application in methacrylated epoxy-based oligomers and their ability in the UV curable hybrid coatings

Abstract

In this study, bromoacetic acid was reacted with 3-(mercaptopropyl) trimethoxy silane (MPTS) and trimethoxy silyl propyl thioacetic acid (TSTA) was produced. Also, bromoacetic acid was reacted with 3-(triethoxysilyl) propylamine (APTS), and triethoxysilyl propylamino acetic acid (TSPA) was synthesized. Finally, from a reaction between trimellitic anhydride (TMA) and APTS, trimellitylimidopropyl triethoxysilane (TMIS) resulted. In all reactions mentioned above, a carboxylic acid head and a trialkoxy silane tail including reactants were obtained. Furthermore, hybrid coatings based on methacrylated bisphenol A epoxy (MBAE) and synthesized carboxylic acids were obtained by photopolymerization. Polycarbonate substrates were utilized for preparation of transparent hybrid films. Then, the solvent resistance, hardness, gel content as well as the adhesion of coatings were measured as physical and mechanical properties. According to the obtained results, these properties of hybrid coatings improved with the increase in alkoxysilanes and sol–gel precursor contents. The surface morphology was characterized by scanning electron microscopy (SEM). The results showed that silica particles were not dispersed homogenously at the molecular level in the hybrid system. Also, the thermogravimetric analysis results indicated that alkoxysilanes enhanced the thermal oxidative stability of the hybrid coatings.