Surface modification of cellulose nanowhiskers for application in thermosetting epoxy polymers

Cellulose nanowhiskers (CNWs) were chemically modified with dodecenyl succinic anhydride to obtain hydrophobic CNWs called DCNWs. Surface modification was confirmed by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction. The surface substitution degree determined by X-ray photoelectron spectroscopy was 0.30. Nanocomposites were prepared by incorporating different amounts of DCNWs pre-dispersed in a small amount of acetone into an epoxy matrix. Scanning electron microscope demonstrated that DCNWs dispersed well in the epoxy matrix. A strong interaction was proved between the DCNWs and epoxy matrix, as results of which the nanocomposites exhibited an obvious increase in T _g by about 30 °C, simultaneous increases in tensile strength, Young's modulus, and strain at break; and an improvement in the hydrothermal properties. Compared with the neat epoxy, the nanocomposite containing 3.5 wt% of DCNWs exhibited an increase in tensile strength by 82 %, Young's modulus by 21 %, and a strain at break by 198 %.