POSS containing hyperbranched polymers as precursors for magnetic Co@C-SiOx ceramic nanocomposites with good sinter–resistant properties and high ceramic yield

Abstract

For the first time, a POSS and cobalt containing hyperbranched polymer (HP2-Co) was synthesized via a convenient A₂ + B₃ strategy for solid-state pyrolysis to generate magnetoceramics. For comparison, its analogue (HP1-Co) without the POSS group was also prepared. After pyrolysis, the ceramic obtained from HP2-Co with POSS groups had a unique Co@C-SiO_x structure, and its diameter almost remained unchanged with increasing the pyrolysis temperature, showing good sinter–resistant properties. However, the nanoparticles obtained from HP1-Co sintered seriously with increasing temperature. More importantly, the ceramic yields of HP1-Co and HP2-Co were 82% and 90%, respectively, much higher than those of the linear polymers (58–73%). All the produced ceramics showed good magnetic properties, with the saturation magnetization ranging from 40.8–69.0 emu g⁻¹, making them promising candidates for the actual applications.