In situ loading ultra-small Cu2O nanoparticles on 2D hierarchical TiO2-graphene oxide dual-nanosheets: Towards reducing fire hazards of unsaturated polyester resin

Fire hazards have seriously hindered the commercial application of unsaturated polyester resin (UPR), and polymer inorganic nanosheet nanocomposites hold great promise in improving their flame-retardant properties. Herein, the hierarchical structured Cu2OTiO2GO nanosheets were synthesized and characterized by XRD, Raman, TEM and XPS. Then Cu2OTiO2GO nanosheets were incorporated into UPR matrix to obtain flame-retardant UPR nanocomposite. Incorporation of 2 wt% Cu2OTiO2GO nanosheets into UPR matrix resulted in an obvious reduction in PHRR and THR by 29.7 and 19.1%. TG-IR-MS results revealed that toxic pyrolysis gas such as benzene, CO and aromatic compounds greatly were decreased. In addition, RIIR spectra demonstrated the limited influence of Cu2OTiO2GO nanosheets on thermal degradation of UPR matrix, and SEM images of char residues showed that Cu2OTiO2GO nanosheets could improve their compactness. Based on the analysis of gaseous and condensed phase, a plausible flame-retardant mechanism was hypothesized to elaborate how Cu2OTiO2GO nanosheets work inside the flaming UPR nanocomposite. This innovative idea may be expanded to other polymer system and open a new door to develop polymeric nanocomposites with high performance.