Surface-covalent functionalized graphene oxide sheets with hyperbranched polysiloxane and Mn ion for cyanate ester resin: Towards lower curing temperature and higher performance

Achieving lower curing temperature and higher properties has been the significant target for developing heat-resistant thermosetting resins . Herein, a facile covalent approach has been built to fabricate functionalized graphene oxide (HBP@GO/MnF) through grafting hyperbranched polysiloxane (HBP) and hybridizing metal–organic framework with Mn 2+ (MnF), which has been proved to have desirable abilities of simultaneously decreasing curing temperature as well as improving toughness and stiffness while maintaining the biggest advantage (low dielectric loss) and high thermal resistance of cyanate ester (BCy) resin. A comparative study demonstrates that the activation from HBP endows HBP@GO/MnF with good dispersion in BCy resin and provides strong interfacial action between HBP@GO/MnF and BCy resin. When the loading of HBP@GO/MnF is as small as 0.5 wt%, the peak temperature of curing reduces to 278 °C from 313 °C of BCy, meanwhile severally about 60%, 98%, 120% and 93% increased flexural strength , flexural modulus, impact strength and fracture toughness are achieved. In addition, all modified BCy resins post-cured at 220 °C/4 h have better mechanical properties and higher heat resistance than pure BCy resin post-cured at 240 °C for 4 h. These outstanding performances prove that HBP@GO/MnF is promising filler for fabricating new resins with higher performances and better curing feature.