Multifunctional Dual-Pore Network Aerogel Composite Material for Broadband Sound Absorption, Thermal Insulation, and Fire Repellent Applications

Highly porous aerogels are greatly anticipated for multifunctional utilization, including building insulators, sound absorbers, filters, energy storage devices, etc. Currently, most aerogels are usually resourced from fossil fuels and nonrenewable materials and often require an additional step to provide multifunctionality. In this work, a facile strategy is presented to fabricate a multifunctional scaffold valorizing polypropylene mask filters intercalated by calcium alginate (CAP) through an ice templating method to generate a dual-pore structure with fibrillated networks. The exploitation of the enhanced porous cell wall and the intrinsic properties of the constituting materials provided a platform for multifunctionalities such as sound absorption, thermal insulation, and fire retardant properties. The dual-pore attribute implemented an effective broadband frequency sound absorption. The outstanding acoustic performance can be ascribed to the structural integrity of the dual-pore microchannels that dissipate the sound within the interconnected fiber wall resonating the sound in different directions. This structural orientation also endows excellent thermal transport properties for a broad range of temperature conditions depleting energy transport. Moreover, the resultant material exhibited flame retardant properties without any further functionalization but through its structural attributes and innate nature of the compounding material. Upon pyrolysis, the structure networks form a char layer that acts as a fire-repellent barrier to induce fire propagation. Without further modification, the generated aerogel can serve as a base platform for sustainable multifunctional scaffolds. This strategy is realized to be a universal technique to prepare highly porous allotropic aerogels with various functionalities.