A novel poly(p-phenylene benzobisoxazole) (PBO)-based three-phase silk-cocoon network structure nanocomposites with enhanced dielectric properties

Nanocomposites with great thermal stability and excellent dielectric properties play a vital role in the development of high-temperature resistant capacitors. A facile yet effective method to synthesize enhanced dielectric properties of thermostable three-phase poly(p-phenylene benzobisoxazole) (mCCTO@CFGO/PBO) nanocomposite films is demonstrated in this work. The amino-functionalized oxide CaCu 3 Ti 4 O 12 nanoparticles (mCCTO) are enwrapped by the carboxyl-functionalized ultrathin graphene shells (CFGO), forming the silk-cocoon structure to achieve homogeneous dispersion in the matrix. The final films are fabricated via in situ polymerization by introducing the mCCTO@CFGO nanoparticles into the PBO precursor polymer. The mCCTO@CFGO/PBO nanocomposite films exhibit high thermal stability (the 5% thermal decomposition temperature is 655 °C), while the unique silk-cocoon structure effectively confers the high dielectric constant up to 86.9 and ultra-low dielectric loss (0.063) with the loading of 10 wt% mCCTO@3 wt% CFGO/PBO at 1 kHz and 200 °C. This promising strategy accelerates the development of electronic devices used under high temperatures.