Preparation of wheat straw-based aerogel and the research of it’s flame retardancy

Abstract

Using waste biomass resources wheat straw(WS) as raw material, sodium alginate(SA) as basic skeleton and phytic acid(PA) solution as flame retardant, WS based composite aerogel(CA) was prepared in this research. Single factor experimental variables were used to optimize the preparation process conditions, and the relevant properties of CA were determined by FT-IR, limiting oxygen index, Raman test, etc. The experimental results show that the preparation conditions with better performance: the mass ratio of SA to WS was 1:1, the concentration of PA was 75%, the mass ratio of PA to SA was 1:4, and the mass ratio of PA to WS was 1:4. The obtained CAs have low density characteristics, the lowest density is 0.0122 g/cm3, the limiting oxygen index(LOI) attains a high level of 30.2%, while the vertical burning test(UL-94) demonstrates an impressive V-0 grade. FT-IR analysis showed that WS, SA and PA were physically cross-linked. The results of thermogravimetry analysis(TGA) showed that WS based CA had similar thermal degradation behavior，and raman analysis showed that the mixture of SA/WS/PA CA greatly improved the graphitization degree of the CA material, which helped to improve the stability of residual carbon ratio. WS produces no additional carbon dioxide throughout its life cycle, and the use of waste biomass WS in whole components does not need to be separated in advance, which is good for the environment, and reduces a lot of manpower, material and financial resources, and has more economic and application prospects. It is meaningful for the high-value utilization of waste resources, turning waste into treasure.