Melamine-based bifunctional composite aerogels: Recent advances in flame retardancy and microwave absorption

With electronic information technology developing so quickly, fire safety and electromagnetic microwave pollution issues have become increasingly severe, posing significant hazards to human health and public safety. Melamine foam (MF), as a promising lightweight material, has been widely utilized in transportation, agriculture, aerospace, electronics, construction, and many fields owing to its sound absorption, safety advantages, superior thermal insulation, and ease of processing. This review comprehensively summarizes the recent advances in MF and melamine-based aerogel for electromagnetic wave absorption (EMA)/flame-retardant bifunctional composites. A special focus is on melamine-based aerogel manufacturing techniques, as well as the fundamental mechanisms underlying their flame-retardant and electromagnetic microwave absorption performances. In addition, the development of melamine-based aerogels with enhanced EMA and flame-retardant properties is systematically discussed. Benefiting from their unique structural designs and synergistic effects, these materials exhibit outstanding EMA performance and remarkable flame-retardant efficiency. Moreover, most melamine-based aerogels also possess additional functionalities, including excellent thermal insulation, sound absorption, and oil-water separation capabilities. Finally, the current challenges associated with melamine-based bifunctional composites are emphasized, and suggestions are made for future lines of inquiry.