Fabrication and Characterization of a High-Strength Polyimide/Thermoplastic Polyurethane Composite Aerogel with Hydrophobicity and Low Thermal Conductivity
Yihao Nie, Xibin Yi, Xinfu Zhao, Shimo Yu, Minna Zhang, Jian Zhang, Guoliang Dou, Mengdi Wang
Abstract
Polyimide (PI) aerogel has surfaced in research and development as a result of its heat resistance, flame retardancy, and low dielectric constant. However, it is still a challenge to reduce the thermal conductivity while improving its mechanical strength and retaining hydrophobicity. Herein, the PI/thermoplastic polyurethane (TPU) composite aerogel was synthesized by coupling TPU with PI via a novel method of chemical imidization combined with freeze-drying technology. With this technique, PI aerogel with excellent comprehensive performance is produced. Interestingly, the volume shrinkage of the composite aerogel decreased from 24.14 to 5.47%, which leads to low density (0.095 g/cm 3 ) and elevated porosity (92.4%). In addition, strong mechanical strength (1.29 MPa) and high hydrophobicity (123.6°) were achieved. More importantly, PI/TPU composite aerogel demonstrated a low thermal conductivity of 29.51 mW m –1 K –1 at ambient temperature. Therefore, PI/TPU composite aerogel can be a promising material for hydrophobic and thermal insulation applications.