Improving the flame retardancy and smoke suppression of ethylene vinyl acetate composites by introducing the hybrid material of Zn/TiO2@AKaol

Ethylene vinyl acetate copolymer (EVA) is widely applied in many important fields, but its broader utility is impeded by its flammability. To address this problem, the pre-acidified kaolinite (AKaol) by sulfuric acid was further dealt with TiO2 loading and Zn2+ doping to obtain Zn/TiO2@AKaol to improve the flame retardancy and smoke suppression of EVA composites containing intumescent flame retardants (IFR) typically. The results showed that the addition of 1 wt% Zn/TiO2@AKaol improved the flame retardancy and reduced the smoke release of EVA/IFR composite. The limiting oxygen index (LOI) value of the EVA/IFR composite containing Zn/ TiO2@AKaol increased to 32.7 % from 27.3 % of EVA/IFR composite. In the cone calorimeter test (CCT), the peak heat release rate (pHRR) and total heat release (THR) values were reduced to 297.5 kW/m2 and 98.8 MJ/ m2 from the 409.9 kW/m2 and 109.3 MJ/m2 of EVA/IFR composite, respectively. Meanwhile, the values of total smoke production (TSP) in the CCT and smoke density tests in building materials were reduced to 13.5 m2 and 33.39 % of EVA/IFR/Zn/TiO2@AKaol composite from 18.4 m2 and 63.91 % of EVA/IFR composite, respectively. Based on the mechanism analysis, it was proposed that Zn/TiO2@AKaol not only promoted the production of P & sdot; in advance, but also increased a cross-linked structure char in the condensed phase to achieve flame retardancy and smoke suppression of EVA composites.