This work presents the preparation and property characterization of a biomass gelatin (GA)-based aerogel. Halloysite nanotubes (HNTs) were used to improve the mechanical strength, pore size distribution, and thermal stability of the aerogel. Polyethyleneimine (PEI) and (3-glycidyloxypropyl)­trimethoxysilane (GPTMS) were utilized to increase the interfacial interaction between HNTs and GA through chemical cross-linking. Green, sustainable, and low-cost composite aerogels were prepared by “cogel” and freeze-drying techniques. The experimental results show that the HNTs/GA composite aerogel has a low density (31.98–57.48 mg/cm3), a high porosity (>95%), a low thermal conductivity (31.85–40.16 mW m–1 K–1), and superior moldability. In addition, the mechanical strength and thermal insulation properties of the HNTs/GA composite aerogels with a “thorn”-like lamellar porous network structure are different in the axial direction versus the radial direction. The maximum compressive strength, maximum compressive modulus, and corresponding specific modulus in the axial direction were 1.81 MPa, 5.45 MPa, and 94.8 kN m kg–1, respectively. Therefore, the biomass/clay composite aerogel will be a sustainable and renewable functional material with high mechanical strength and thermal insulation properties, which is expected to further promote biomass and clay for high value utilization.

No abstract

In this work, hollow glass microspheres (HGM) were introduced into the polyimide matrix as an effective reinforcement filler to improve the mechanical and thermal insulation properties of the polyimide foams (PIF). The HGM was surface-modified with the silane coupling agent to enhance the interfacial compatibility with PIF. Experimental results revealed that the average cellular diameter of PIF decreased obviously with the addition of the modified HGM (M-HGM). The apparent density of foams also increased from 15.85 to 18.34 kg/m3 when the M-HGM combination was changed from 0 to 12 percent (wt.%). Compared with the pure PIF, the composite foams added 8 wt.% M-HGM showed high compression strength (65 kPa) and compression modulus (1147 kPa), resulting in a distinct enhancement in mechanical properties. Furthermore, the addition of M-HGM filler also improved the thermal insulation performance of PIF, which exhibited the minimum thermal conductivity of 29.48 mW·m−1·K−1 with 8 wt.% M-HGM. Thus, considering the improved mechanical and insulation properties of the prepared PIF, it could be a promising candidate for the high temperature-resistant thermal insulating applications.