The effect of nitrile-functionalized nano-aluminum oxide on the thermomechanical properties and toughness of phthalonitrile resin

Abstract

Resorcinol-based phthalonitrile (R-CN)/nano-aluminum oxide (Al 2 O 3 ) nanocomposites were prepared via a two-step approach. Firstly, Al 2 O 3 was functionalized with nitrile groups on the surface of Al 2 O 3 nanoparticles, which was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy (SEM). The effect of nano-Al 2 O 3 particles on thermomechanical and flexural properties has been evaluated for different weight ratios ranging between 0% and 5%. Compared with pure nano-Al 2 O 3 , nitrile-functionalized Al 2 O 3 (CN-Al 2 O 3 ) particles showed a more significant enhancement effect on the properties of R-CN resin. The storage modulus of nanocomposite with 5 wt% CN-Al 2 O 3 reaches 2679 MPa at 25°C, which is much higher than that of the pure R-CN resin. For 3 wt% CN-Al 2 O 3 -reinforced R-CN composites, it showed an increase of 54.84% in flexural strength and 21.48% in flexural modulus. SEM was employed to explore the fracture surface of composites. Micrographs of fracture surface analysis confirmed that the toughness of R-CN resin can be improved significantly by incorporating CN-Al 2 O 3 nanoparticles.