Investigating mechanical behaviors of silica nanoparticle reinforced composites

The research is aimed to investigate the mechanical behaviors of epoxy-based nanocomposites reinforced with spherical nanoparticles. Five different contents of silica nanoparticles - 5, 10, 15, 20, and 40 wt% - were introduced in the samples. Through a sol-gel technique, the silica particles with a diameter of 25 nm were exfoliated uniformly in the epoxy matrix. Experimental results obtained from tensile tests indicate that the modulus of nanocomposites increases with the increment of particulate inclusions, and the enhancing behavior is coincided with the model predictions obtained from the Mori-Tanaka micromechanical model. In addition, the fracture tests conducted on single-edge-notch bending specimens reveal that the inclusion of nanoparticles can effectively increase the fracture toughness of the nanocomposites. Furthermore, the extent of the enhancement is more appreciable in the brittle matrix system rather than in the ductile matrix system. Subsequently, by inserting the silica epoxy mixture into the unidirectional glass fiber through a vacuum hand lay-up process, the glass fiber/silica/epoxy composite samples were fabricated. Results depicted that the in-plane shear strength increases until the increment of particle loadings are up to 10 wt%. In addition, results obtained from the compression tests revealed that the glass/epoxy specimens with 20 wt% silica loading exhibit superior compressive strengths than those that do not contain any silica particles.