Flame retardant cotton fabric modified with silica nanosols containing huntite–hydromagnesite grafted with GPTMS and VTES

Abstract

In this study, the cotton fabrics were coated with silane-based nanosols containing modified huntite–hydromagnesite (HH) via pad-dry-cure process. The modification of HH was carried out by the grafting of (3-glycidyloxypropyl) trimethoxysilane (GPTMS) or vinyltrietoxysilane (VTES) on HH by means of different oxidative agents such as hydrogen peroxide and ammonium persulphate in free radical reaction. Our goal is to improve the embedding of HH in silica film layer on cotton fabric by grafting of GPTMS or VTES on HH. The flame retardancy properties of the cotton fabrics were evaluated according to ash content, limit oxygen index, vertical flame test, cone calorimetry test and differential thermal analysis-thermogravimetric analysis. The increase in ash content, char residue with good structural integrity after burning confirmed the improvement on flame retardancy of the coated fabrics. Fabric properties were also analyzed with add-on, tensile strength test, water vapor permeability, air permeability, whiteness and yellowness index. While the inherent properties of fabrics modified with HH grafted with VTES did not significantly change, the fabrics modified with HH grafted with GPTMS exhibited higher tensile strength and lower whiteness index with regard to the untreated fabrics. The SEM-EDX and FTIR-ATR analysis have showed that the fabrics modified with HH grafted GPTMS have relatively intensive film layer and more content of silica and HH on their surface, which demonstrated the development of embedding of HH grafted with GPTMS in silica layer.