Phytic acid as an eco-friendly flame retardant for silk/wool blend: A comparative study with fluorotitanate and fluorozirconate

Because of the urgent needs for eco-friendly textiles and environmental protection, the development and application of sustainable flame retardant (FR) agents have become a research hotspot In this work, naturally occurring and phosphorus-rich phytic acid (PA) was used to improve the FR ability of silk/wool blend using an adsorption technique, and comparative studies were conducted on the application conditions, FR effect, smoke suppression, heat release capability, catalytic char forming, and FR mechanism of PA and conventional FR agents (K2TiF6 and K2ZrF6). The application of PA at pH 1.3-2.0, moderate temperature, and proper concentration remarkably improved the FR ability of the blend as per the limiting oxygen index and vertical burning assessments. Although the PA treated blend was inferior to the K2TiF6 treated blend in initial FR ability, it exhibited better FR effect after repeated washing. Among three FR agents used, PA had the best smoke suppression, lowest heat release capability, highest ability to inhibit the thermal oxidation of the degraded products of fibers, and best catalytic char forming effect. PA acted as an effective FR in the solid phase. However, the application of PA had a shortcoming of decreasing the whiteness of the blend. (C) 2018 Elsevier Ltd. All rights reserved.