Enhanced fracture toughness of nanostructured carbonfiber reinforced poly(urethane-isocyanurate) composites at low concentrations

CHIACCHIARELLI LEONEL MATIAS; ROBERTO PETRUCCI; LUIGI TORRE

POLYMER ENGINEERING AND SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2017

0032-3888

Carbon fiber reinforced poly(urethane-isocyanurate)-nanosilica composites CF-(PUI-NS) were manufactured by means of the vacuum-assisted resin transfer moulding technique (VARTM) at very low NS concentrations (0?4 wt%). The high strain to failure of the PUI matrix (>7%) affected tensile tests by CF reorientation. Both the tensile strength and strain to failure were highly dependent on its kinematics. CF(PUI-NS) caused an increase of the statictoughness with a maximum improvement of tensile strain to failure and modulus of 128.8% and 139% at 1 wt% and 2 wt% of NS, respectively. The interlaminar shearstrength (GIC) of the composites showed both a deterioration of 212.9% and an improvement of 19.9% for NS concentrations of 1 wt% and 4 wt%, respectively. Regardless of the GIC value, all of the composites prepared with NSpresented secondary maxima of the force versus displacement plots, indicating a substantial arrest of the crack propagation velocity after delamination started.Fractographic analysis revealed several features, such as fiber pull-out, bridging as well as river patterns whereas the composites prepared with NS behaved in a more ductile fashion due to the presence of river patterns and areduced fiber pull-out.