Preparation of a novel bio‐based aerogel with excellent hydrophobic flame‐retardancy and high thermal insulation performance

Abstract Sodium‐alginate‐based aerogels possess wide prospects in the fields of packaging, aerospace, industrial construction and transportation because of their environmental compatibility and thermal insulation, but it is still a challenge to obtain a sodium alginate‐based aerogel with high flame retardancy and good thermal insulation. Herein, a sodium‐alginate‐based aerogel with high flame retardancy, thermal insulation and good hydrophobic properties was prepared by two‐step crosslinking strategy of phytic acid and metal ions and liquid phase deposition of trans‐cinnamic acid. As a result, the prepared SA/PA Mn + aerogels obtained excellent flame retardancy (UL‐94 V‐0, LOI 50.1%) and rapid self‐extinguishing, and SA/PA Mn + aerogels obtained good hydrophobic ability (CA = 134.2°). In addition, the mechanical properties of SA/PA Mn + aerogels have also been improved, the compressive modulus increased from 0.66 to 6.37 MPa, and the specific modulus increased from 15.7 to 140.2 MPa cm −3 g −1 . This research broadens the application of bio‐based flame‐retardant aerogels in the fields of packaging, aerospace, industrial construction and transportation.