Superior intrinsic flame-retardant phosphorylated chitosan aerogel as fully sustainable thermal insulation bio-based material

• Published in: Polymer degradation and stability Vol. 207; p. 110213
• Main Authors: Cui, Hongli, Wu, Ningjing, Ma, Xiaobing, Niu, Fukun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2023
• Subjects: aerogels; Bio-based aerogel; biobased products; biodegradability; Chemical modification; chemical structure; chitosan; degradation; Fourier transform infrared spectroscopy; freeze drying; heat; Heat-insulation material; hydrophobicity; insulating materials; Intrinsic flame retardancy; nuclear magnetic resonance spectroscopy; oxygen; phosphates; Phosphorylated chitosan; pollution; polymers; thermal conductivity; X-ray photoelectron spectroscopy; Phosphorylated chitosan; Chemical modification; Heat-insulation material; Bio-based aerogel; Intrinsic flame retardancy
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2022.110213

•Phosphorylated chitosan (PCS) was prepared in a H3PO4/acetic acid/H2O solution.•The limited oxygen index value of PCS aerogel increased to above 80%.•The peak heat release rate values of PCS aerogels dramatically decreased.•Superior flame-retardant PCS aerogels show promise as new heat insulation material. Owing to the arising environmental pollution and energy-related challenges, the utilization of renewable polysaccharides such as chitosan (CS) in the preparation of biodegradable aerogel heat-insulation materials represents a growing interest. In this study, a simple and low-cost route was proposed to synthesize a phosphorylated chitosan (PCS) with a high substitution degree of phosphate groups in a homogeneous H3PO4/acetic acid solution, and its chemical structure was confirmed using FT–IR spectroscopy, nuclear magnetic resonance, and X–ray photoelectron spectroscopy. An outstanding intrinsic flame-retardant PCS aerogel was directly fabricated via freeze-thawing and freeze-drying process. Remarkably, limited oxygen index values of the PCS aerogels increased to above 80%, and their UL–94 test results achieved V–0 rating. The peak heat release rate and total heat release rate values of PCS-4 aerogel significantly decreased by 91.2% and 73.0% compared with those of chitosan aerogel, respectively. The bio-based PCS aerogel with superior intrinsic flame retardancy, low thermal conductivity, and excellent hydrophobicity shows promise as new sustainable flame-retardant heat-insulation material. [Display omitted]