A sustainable and reactive intumescent flame-retardant containing phytate and triazine-trione for durable functional coating of silk fabric

Abstract

The development of sustainable, efficient and durable flame-retardant (FR) coating for silk fabric using plant-derived phytic acid is of great interest. This work synthesized a novel and reactive intumescent FR agent namely glycidyl phytate isocyanurate (GPIC) through ring-opening addition reaction using phytic acid and 1,3,5-triglycidyl isocyanurate. Then, the durable FR coated silk fabric was developed with GPIC through the surface coating route. The chemical structure of GPIC, and its cross-linking mechanism with silk, the smoke and heat generation performance, flame retardancy and washing durability of coated silk were studied. The coated silk fabric with a weight gain of 13.6 % could self-extinguish and possessed a high limiting oxygen index (LOI) value of 32.5 %. GPIC coating would be covalently cross-linked onto silk fabric and the coated silk fabric could withstand 30 washing cycles, displaying high washing durability. GPIC coating also significantly suppressed the smoke and heat generation of silk fabric during combustion. The coated silk fabrics had high thermal stability and left significant inflated char residues after the burning tests. The intumescent FR performance of GPIC was beneficial from the synergistic effect of phytate and triazine-trione groups.