Mechanical performance and thermal stability of polyvinyl alcohol–cellulose aerogels by freeze drying

Polyvinyl alcohol (PVA)/cellulose nanofibers (CNFs)/Gelatin hybrid organic aerogels were synthesized using a facile and environmentally friendly freeze-drying method. The biobased gelatin acted as a cross-linking agent and combined PVA and CNFs tightly by hydrogen bonds. The composites were characterized and analyzed by various techniques including uniaxial compression test, scanning electron microscopy, as well as thermal conductivity analysis and TGA–DTG analyses. The mechanical properties were strengthened significantly with the introduction of a small amount of gelatin. The modulus of PVA/CNF/G3 was 1.65 MPa, nearly eightfold of the PVA/CNF aerogel and 91 times higher than the neat CNF aerogel. Microstructure analyses revealed the three-dimensional network of the aerogels. The composites also possess good thermal stability, low density, and low thermal conductivity. Therefore they have broad prospects in the field of thermal insulation.