Enhanced Thermal Insulation and Flame-Retardant Properties of Polyvinyl Alcohol-Based Aerogels Composited with Ammonium Polyphosphate and Chitosan

Abstract

Polyvinyl alcohol- (PVA-) based aerogels have attracted widespread attention owing to their low cost, eco-friendliness, and low density. However, the applications of PVA-based aerogels are limited by their flammability. In this study, a flame retardant, ammonium polyphosphate (APP), and a biopolymer, chitosan (CS), were added to polyvinyl alcohol (PVA), and the polymer was further crosslinked using boric acid (H3BO3). In the PVA aerogels, the negatively charged APP and positively charged CS formed a polyelectrolyte complex (PEC) through ionic interaction. Cone calorimetry and vertical burning tests (UL-94) indicated that the PVA composite aerogels have excellent flame retardancy; they could decrease the heat release rate, total heat release rate, and carbon dioxide (CO2) generation. Both PVA/H3BO3 and APP-CS in the composite aerogel could be burned to carbon, and the foamed char layer could act together to impart the PVA composite aerogels with good flame retardancy. Further, the decrease in the temperature at the backside of the aerogels with increasing APP-CS content, as determined by the flame-spraying experiment, indicated that the PVA-based aerogels with APP-CS can also serve as thermal insulation materials. This work provides an effective and promising method for the preparation of PVA-based aerogels with good flame retardancy and thermal insulation property for construction materials.

Aqua‐mediated in situ synthesis of highly potent phosphorous functionalized flame retardant for cotton fabric

“…A wide variety of FR composites have been reported, including synthetic polymers, such as polypropylene (PP), poly (vinyl chloride) (PVC), polyurethane (PU), and polystyrene (PS), and epoxy mixed with inorganic mineral materials such as clay and silica. [5][6][7][8][9][10][11][12] However, researchers restrict the use of such materials because of high production costs and environmental safety issues. 13 Because of their comprehensive properties, the polyvinyl alcohol (PVA) has its status in the polymeric complexes.…”

Green Preparation of Thermal-Insulative, Flame Retardant, and Hydrophobic Silica Aerogel Reinforced Poly(vinyl alcohol) Composites

“…10−12 Various strategies have been developed to overcome two drawbacks. The primary route to improve flame retardancy is to add flame retardants such as ammonium polyphosphate, 13,14 melamine−formaldehyde, 15 and a series of elements containing nitrogen and phosphorus, 16 which have received commercial applications. Researchers also develop methods by including inorganic fillers, nanoclay, 17,18 fly ash, montmorillonite, 19 hydroxyapatite, 20 and Ti 3 C 2 T x , 21 etc.…”

“…Poly­(vinyl alcohol) (PVA), as a biodegradable material with the advantages of low cost, nontoxicity, excellent biocompatibility, chemical stability, and high mechanical properties, is gradually becoming a research hotspot. − However, PVA has two significant shortcomings, i.e., flammability and hydrophilicity, which limit its application in high-temperature and water-sensitive applications. − Various strategies have been developed to overcome two drawbacks. The primary route to improve flame retardancy is to add flame retardants such as ammonium polyphosphate, , melamine–formaldehyde, and a series of elements containing nitrogen and phosphorus, which have received commercial applications. Researchers also develop methods by including inorganic fillers, nanoclay, , fly ash, montmorillonite, hydroxyapatite, and Ti 3 C 2 T x , etc.…”

Modification on nanocellulose extracted from kenaf (Hibiscus cannabinus) with 3-aminopropyltriethoxysilane for thermal stability in poly (vinyl alcohol) thin film composites

“…Owing to its low thermal stability, high ammability has led the PVA to be reinforced with other llers such as graphene, iron oxide, and nanoclays. However, all of these materials are considered non-organic or synthetic llers (Gaaz et al 2015;Luo et al 2021). Other than these, organic llers would give some advantage since they are sustainable and abundantly available from natural resources.…”