Abstract: Composites of CE/PPO/HBP-SiO2 and CE/PPO/nano-SiO2 were prepared using CE modified by PPO as a matrix, and HBP-SiO2 and nano-SiO2 as fillers. Infrared spectroscopy confirmed that hyperbranched polysiloxane was grafted onto SiO2 surface. Differential scanning calorimetry showed that HBPSiO2 and nano-SiO2 had catalytic effect on CE/PPO system, and could reduce the curing temperature. The addition of SiO2 improved the mechanical properties of system, and the addition of HBP-SiO2 showed a better effect than nano-SiO2. The dielectric constant of CE/PPO/HBP-SiO2 composite was less than that of CE, CE/PPO, CE/PPO/nano-SiO2, and the dielectric loss factor was smaller than that of CE and CE/PPO, while higher than that of CE/PPO/nano-SiO2.

Key words: cyanate resin, hyperbranched polysiloxane grafting silica, polyphenyleneoxide, mechanical property, dielectric property