Multi‐crosslinked, ecofriendly flame‐retardant starch‐based composite aerogels with high compression‐resistance

Abstract

To achieve ecofriendly aerogels with high mechanics and fire resistance, naturally‐occurring pea starch was employed as the major substrate, and starch‐based composite aerogels were fabricated by freeze–drying method. The corresponding hydrogels were obtained through successive gelatinization/dissolution of pea starch and polyvinyl alcohol (PVA), formation of precursor hydrogels via cyclic freeze–thawing, followed by treatment with borax aqueous solution. Borax treatment not only results in aerogels with high mechanics, but also endows the aerogels flame‐retardant property. The final aerogels show high compression‐resistance, with a maximum specific compressive modulus achieved at ~44 MPa and the yield strength 665 kPa, owing to the formation of a multi‐crosslinked hybrid network. The maximum limiting oxygen index (LOI) of the aerogels exceeds 34. The peak heat release rate, the heat release capacity, and the total heat release decrease 74.5%, 76.2%, and 73.8% after borax treatment. Moreover, the obtained aerogels demonstrate good thermal stability and thermal insulation. The good performance is conducive for practical application.

Scientometric Review of Sustainable Fire-Resistant Polysaccharide-Based Composite Aerogels

“…The amylose content of starch, for example, might influence the mechanical characteristics of aerogels [68]. Starch, on the other hand, is typically regarded as a naturally flame-retardant substance due to its good char-forming characteristics, which emits CO 2 , CO, and creates a carbon layer upon combustion, hence limiting the spread of heat and oxygen [69]. Despite the outstanding advantages of starch aerogel, there remain some drawbacks, such as low hardness.…”

Scale‐up fabrication and advanced properties of recycled polyethylene terephthalate aerogels from plastic waste

“…In more recent advances in aerogel production, freeze drying has been employed to dry the gels through sublimation. [31][32][33][34][35][36][37][38][39][40][41][42][43] As the gels are first frozen to a solid state and sublimated into a gaseous state, it bypasses the capillary forces in the drying process whilst maintaining the aerogel structure. With this drying method, no solvent exchange is required and production can be up to 2.5 times faster.…”

“…To circumvent such issues, additional chemicals are required to modify and strengthen the networks of the aerogel prior to drying. In more recent advances in aerogel production, freeze drying has been employed to dry the gels through sublimation 31–43 . As the gels are first frozen to a solid state and sublimated into a gaseous state, it bypasses the capillary forces in the drying process whilst maintaining the aerogel structure.…”

Eco‐friendly production and performance evaluation of water‐resistant cellulose nanofiber bioaerogels

“…10 As a result, they have found applications in diverse fields such as flame retardant, water treatment, biosensing, drug delivery, dressing and wound healing, and also tissue scaffolding. 11,12 Cellulose, a polymer abundantly found in plant cell walls, is gaining significant attention due to its biocompatibility, noncytotoxicity, and environmental sustainability. 3 Various approaches have been employed to create cellulose aerogels, resulting in materials of remarkably low density, characterized by the random arrangement of cellulose elementary fibrils in a three-dimensional network.…”

“…Additionally, these bioaerogels exhibit properties similar to those of synthetic polymers and inorganic aerogels 10 . As a result, they have found applications in diverse fields such as flame retardant, water treatment, biosensing, drug delivery, dressing and wound healing, and also tissue scaffolding 11,12 …”