Synthesis and Characterization of bis (5-Cyanato Naphthalene-1 Oxy) Methyl Phenyl Silane Epoxy Composites

Abstract

A novel siloxane containing dicyanate was synthesized from the condensation reaction of dichloro methyl phenylsilane with 1, 5 dihydroxynaphthalene in a 1 : 2 ratio using triethylamine as catalyst. A new dicyanate was prepared by treating CNBr with synthesized silane containing diol in the presence of triethyl amine as catalyst at —10 to 5 °C. The dicyanate was characterized by Fourier transform infrared spectroscopy (FTIR) and NMR. The curing reaction of the prepared dicyanate and epoxy blends was studied using differential scanning calorimetry. The prepared dicyanate was blended with commercial epoxy resin in different ratios (3, 6 and 9%) and cured at 120 °C for 1 h, 150 °C for 1 h, 220 °C for 1 h using diamino diphenyl methane as the curing agent. The composite laminates with glass fiber were also fabricated using the same composition. Cured neat resin and epoxy blends were characterized by FTIR. The mechanical properties such as tensile strength, flexural strength, and fracture toughness of the composites were measured by adopting ASTM D 3039, D 790, and D 5528, respectively. The tensile strength increased with increasing cyanate content (3, 6, and 9%) from 55 to 62 MPa. Dynamic mechanical analysis shows that with increasing cyanate content in the composite the storage modulus moderately increased in comparison with the neat epoxy composite. There was not much difference in the values of storage modulus at 50 °C and that at 100 °C, showing that the synthesized cyanate has better thermo mechanical characteristics. The flame retardant property of epoxy—cyanate blend was observed to be 50, 36 and 25 s for 3, 6 and 9%, respectively, which showed that the silane-containing cyanate polymer had better flame retardant properties.