Modification of dicyanate ester resin by liquid carboxyl-terminated butadiene acrylonitrile copolymer

Bisphenol A dicyanate ester (BADCy) was modified with liquid carboxyl-terminated butadiene acrylonitrile (LCTBN). The cured BADCy resin was formed through the cyclotrimerization of cyanate functional groups into triazine rings, and there was the chemical reaction between BADCy and LCTBN. Mechanical performance indicated that the introduction of LCTBN into BADCy resin improved the impact strength with maintenance in flexural strength. Scanning electron microscopy (SEM) showed that the pure resin had a smooth glassy fracture surface, whereas cured blends containing LCTBN showed rougher fracture surfaces, and exhibited enhanced impact resistance. The TEM observation showed that the two phases in the cured resins exhibit a good interaction adhesion. Thermograms of BADCy modified with LCTBN showed the little reduction of heat deflection temperature, and a reduction in thermal stability temperature by 30 K. Dynamic mechanical analysis (DMA) showed that the pure BADCy had higher storage modulus (E′) values than that of the BADCy modified with LCTBN, whereas the loss modulus (E″) was lower, and that the glass transition temperature (Tg) of modified BADCy was 229 °C and lower than that (249 °C) of pure BADCy resin.