Low density polyethylene (LDPE) is a widely used polymer in many fields, offering “low toxicity”, electrical insulation, chemical resistance, mechanical performance and processing facility. However, used alone, it has “high flammability” and melt drips, so readily spreading fires.
Here, a one-component intumescent PIN flame retardant (PA-APP) is proposed, based on phosphorus and nitrogen, obtained in a single step reaction between piperazine (a carbon – nitrogen organic ring) and ammonium phosphate –inorganic P-N compound). The PA-APP combines in one component the acid source, blowing agent and charring agent necessary for intumescent flame retardancy, with 7% carbon content. A loading of 30% PA-APP achieved UL94-V0 (3.2mm) but did not prevent dripping. Although this FR loading is quite high, it is better than total loadings of multiple-component intumescent FR systems. This loading of PA-APP significantly modified the polymers mechanical properties, and further work may be needed to address this.
“An Efficient Halogen-free Flame Retardant for Polyethylene: Piperazine modified Ammonium Polyphosphates with Different Structures”, Liao et al., Chinese Journal of Polymer Science Vol. 34, No. 11, (2016), 1339−1353 http://dx.doi.org/0.1007/s10118-016-1855-8 See also PA-APP in polyethylene in Dong et al., pinfa Newsletter n°67.