Fabrication and investigations of G-POSS/cyanate ester resin composites reinforced by silane-treated silica fibers

Modified cyanate resins (G-CE) and functionalized silica fibers (K-SFs) were obtained by introducing glycidyl polyhedral oligomeric silsesquioxane (G-POSS) and γ -aminopropyltriethoxy silane coupling agent (KH-550), respectively. G-CE and K-SFs were then used to fabricate K-SFs/G-CE wave-transparent composites. The activation energy of the G-CE blends decreased to 49.80 kJ/mol, which led to a decrease in the curing temperature from 274 °C to 254 °C. The contact angle of the functionalized silica fibers increased considerably to 107.4°; this modified the interfacial compatibility, which enhanced the mechanical properties . The K-SFs/G-CE composite had a maximum flexural strength of 548.1 MPa and flexural modulus of 19.3 GPa, which were increases of 86.7% and 48.5% compared to the corresponding values of SFs/CE composite (flexural strength of 293.5 MPa and flexural modulus of 13.0 GPa). In addition, the ε and tan δ of the K-SFs/G-CE composite decreased to 2.63 and 3.3 × 10 −3 , respectively, which were respective decreases of 6.5% and 23.0% compared with the corresponding values of SFs/CE composite ( ε of 2.76 and tan δ of 4.6 × 10 −3 ). Hence, the resulting K-SFs/G-CE composites are good candidate materials for high performance wave-transparent composites.