High-efficient flame retardant ethylene-vinyl acetate composites by incorporating monomolecular IFR and its pyrolysis behavior

Highly efficient flame retardant and excellent mechanical performance was critical for the application of ethylene vinyl acetate copolymer (EVA) composites. Herein, a monomolecular intumescent flame retardant poly(piperazine methylphosphonic acid pentaerythritol ester) defined as PPMPPE was incorporated into the EVA matrix, and the flame retardancy, mechanical performance of EVA composites were investigated. When 21 wt% PPMPPE was incorporated, the limiting oxygen index (LOI) of 1.6 mm EVA/PPMPPE composites was increased from 18.2 % for neat EVA to 27.5 %, and it achieved UL-94 V-0 grate during vertical burning tests. Meanwhile, the cone calorimetry tests indicated that the peak value of heat release rate and total heat release of FR-EVA composites were obviously reduced by 41.1 % and 27 % compared to neat EVA. The analysis of flame-retarded mechanism for EVA/PPMPPE indicated that PPMPPE facilitated the decomposition of EVA and formed an expanding char layer, and it possessed barrier effect in condensed phase. In addition, the PPMPPE could exert free radicals quenching effect and in gaseous phase. Therefore, the PPMPPE endowed the EVA matrix with good flame-retardant efficiency. Meanwhile, the mechanical performance of EVA/21 wt% PPMPPE composites was well maintained, and its tensile strength and elongation at break decreased by 21.9 % and 14.4 %, respectively. This research work provided a feasibility approach for producing EVA composites with excellent flame-retardant and mechanical performance. [Display omitted] •A monomolecular intumescent flame retardant, PPMPPE, was utilized to prepare flame-retardant EVA composites.•EVA/PPMPPE composites possessed excellent flame-retardant and mechanical performance.•The pyrolysis behavior was comprehensively investigated through Py-GC/MS.•PPMPPE exerted flame retarded effect both in condensed and gaseous phase.