Synthesis and performance evaluation of polyurethane/silica hybrid resins

Purpose - The aim of this paper is to synthesise polyester/silica hybrid resins and their hybrid polyurethanes via in situ (IS) and blending (BL) methods and to evaluate the effect of preparation method, interaction type and silica content on the physico-chemical and thermal properties of polyurethane/silica (PU/Silica) hybrid coatings. Design/methodology/approach - Silica particle-containing silica sol was prepared according to Stober method using tetraethylorthosilicate as the precursor and then introduced into polyester matrix by in situ and direct blending method. The modified polyester/silica resin was further crosslinked with TMP-TDI adduct to synthesise PU/Silica hybrid coatings and studied for thermo-mechanical, physico-chemical properties. Findings - It was found IS polymerisation caused more polyester segments to chemically bond onto the surface of silica particles than BL process. Results also reveal that due to stronger interaction between silica particles and PU matrix, hybrid resins prepared by IS method confers better properties than BL method and exhibit optimal properties at the critical concentration of 8 wt% silica. Research limitations/implications - In the present study, silica particles are used to modify properties of polyurethane resins. Many other countless combinations in terms of inorganic filler or organic matrices can be explored to obtain a wide range of interesting properties and applications. Practical implications - The results obtained in this study will be extremely useful to enhance the understanding of this class of hybrid materials. Originality/value - Hybrid organic-inorganic networks offer a new area of material science that has extraordinary implications for developing novel materials that exhibit a diverse range of multi-functional properties.