Thermally Insulating and Flame-Retardant Polyaniline/Pectin Aerogels

Biomass-based thermally insulating and flame-retardant polymer aerogels were fabricated from renewable pectin (PC) and aniline via polymerization–coagulation and a supercritical drying process. A special physical cross-linking action existed between PC and polyaniline (PA). The resultant aerogels showed three-dimensional networks with hierarchical pores and high surface areas (103–205 m² g^–1). With benefits from the cross-linking structure, the pectin-based aerogels exhibited good compressive strengths (4.7–9.2 MPa) and water resistance. The results from thermal conductivity measurements and thermogravimetric analysis revealed that these aerogels also had low thermal conductivity (0.033–0.038 W m^–1 K^–1) and considerable thermal stability. The limiting oxygen index, vertical burning tests, microscale combustion, and cone calorimetry tests further confirmed that the inherently low flammability of the aerogels could be achieved by the flame retardancy of PA and the cross-linking action between PA and PC. These aerogels with good mechanical properties, water resistance, and low thermal conductivity and flammability show promising prospects in the field of thermal insulation.