Glycerol-based polymer adhesives reinforced with cellulose nanocrystals

Biodegradable adhesives are of great scientific and technological interest as an alternative to conventional commercial products, which generally can release toxic substances and take a long time to degrade. Composites using biodegradable polymers synthesized by polycondensation of glycerol and diacids, i.e., poly(glycerol succinate), PGSu, poly(glycerol maleate), PGM, and poly(glycerol maleate-co-succinate), PGMSu, reinforced with cellulose nanocrystals (CNC) were used as adhesives for Angelim (Vatairea heteroptera Ducke). CNC were added at 0, 5, 10 and 20 wt% to the glycerol-derived polymers in order to evaluate their effect on mechanical properties. Polymers and composites were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Adhesive joints were prepared using the synthesized glycerol-based polymers, and poly(vinyl acetate), PVAc, for comparison purposes. Thermal analyses indicated that most of the glycerol-based polymers tested are stable up to 260 °C while adhesion tests indicated that adhesives containing CNC showed superior shear strength as compared to pristine polymers and PVAc. These results suggest that the addition of cellulose nanocrystals (CNC) is a viable approach to tailor the mechanical and adhesive properties.