Novel coating flame retardant APP@UiO for preparation of flame retardant unsaturated polyester resin composites

A novel coating flame retardant named APP@UiO was successfully synthesized by in-situ synthesis of UiO-66-NH2 on the surface of APP. Its structure was characterized by fourier transform infrared (FTIR) X-ray diffraction(XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The effects of APP@UiO on the flame retardant properties and mechanical properties of unsaturated polyester, as well as their flame retardant mechanism, were comprehensively analyzed. The flame retardant properties of UPR composites were studied through limiting oxygen index (LOI) and cone calorimeter test (CCT). When the addition amount of APP@UiO was 10 wt%, the peak heat release rate (pk-HRR) value and the maximum smoke yield (SPRmax) value of UPR composites decreased by 61.34% and 37.5%, respectively, compared with pure UPR, and the LOI value reached 31.2%. The impact performance test of UPR composite was carried out to explore its mechanical properties. The research data showed that the existence of organic ligands in APP@UiO can improves the deterioration of mechanical properties of UPR caused by APP.