Effects of Dimethyl Methylphosphonate, Aluminum Hydroxide and Ammonium Polyphosphate on the Flame Retardancy and Thermal Properties of Unsaturated Polyester Resin

The flame-retardant unsaturated polyester resin with dimethyl methylphosphonate (DMMP), aluminum hydroxide (ATH) and ammonium polyphosphate (APP) were prepared and found to exhibit a high flame-retardant efficiency and low cost. The different dosages of flame retardant effect on the flame retardant were evaluated based on limiting oxygen index (LOI) measurements, vertical burning test (UL94), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). A LOI value of 29.8% and a UL-94 vertical burning V-0 rating was achieved for UPR with 10phr DMMP, 15phr ATH and 9phr APP. In the presence of DMMP, ATH and APP, the dense char structure were produced in the combustion process of UPR.