Highly elastic and multifunctional polyimide/Ti3C2TX Mxene composite aerogels for thermal insulation, flame retardancy and oil absorption

Traditional oil absorption and oil-water separation methods have significant shortcomings such as low efficiency, high cost and environmentally unfriendly, developing efficient oil absorption and recyclable recovery materials has become more desirable for industrial applications. Herein, we fabricate the anisotropic polyimide (PI)/Ti 3 C 2 T x MXene composite aerogels with highly elastic mechanical performance and outstanding flame retardancy, thermal insulation and oil absorption properties via an unidirectional freeze drying method. The introduction of strong hydrogen bonding interactions between Ti 3 C 2 T x and PI matrix is beneficial to the structure integrity and mechanical properties of the composite aerogels. The samples show excellent mechanical properties along the axial direction and highly elastic properties along the radial direction. The compressive modulus and strength of the T 1 P 4 composite aerogel are 5.16 and 0.55 MPa, respectively, and only the minimal plastic deformation and low energy loss coefficient can be observed for the composite aerogel even after 500 compression cycles. Moreover, the PI/Ti 3 C 2 T x composite aerogels has low thermal conductivity, superior flame retardancy and thermal insulation, and excellent oil absorption properties. The surface temperature is 40.6 °C for the T 2 P 1 composite aerogel with 15 mm thickness after annealing on the hot stage at 180 °C for 5 min. The water contact angle of the T 1 P 4 composite aerogel is 123°, and the oil absorption capacity of lubricant oil is 1126%. Furthermore, the composite aerogel exhibits stable oil absorption capacity even after 50 cycles, which demonstrates great potential for practical applications in cyclic oil absorption.