摘要
Developing high-performance composites for maglev train cables that combine excellent flame retardancy, mechanical properties and fatigue resistance is currently a significant challenge in special cable industry. Herein, a multifunctional reactive phosphorus nitrogen flame retardants (UPMDM) with flame retardant and filler surface modification functions was synthesized, and it was employed to control the polymer matrix-filler interactions and the microstructure of ethylene-vinyl acetate copolymer (EVA)-based composite during melt blending. Phosphorus-nitrogen composite flame retardant (MH@UPMDM) could be preformed before melt blending or formed in-situ during melt blending by the reaction between the isocyanate group (-NCO) of UPMDM and the hydroxyl group on the surface of magnesium hydroxide (MH), and the effect of processing type (physical blending/chemical grafting/in-situ reaction) on dispersion kinetics of MH in EVA matrix was investigated. The results indicate preformed MH@UPMDM can play a role in rigid crosslinkers to construct organic-inorganic hybrid network, thus effectively control the dispersion kinetics of the fillers and the filler-matrix interaction in the EVA matrix. Compared with EVA/MH composites, the elongation of EVA/MH@UPMDM composites is increased by nearly 2.2-fold, while it also exhibits an excellent fatigue-resistance under 1.0 × 10 4 th cycles. Furthermore, MH@UPMDM can significantly enhance the flame retardant properties of the composites, the limiting oxygen index (LOI) of EVA/MH@UPMDM composite reaches 33.6%, while its peak heat release rate (PHRR) and total heat release (THR) decreases to 277.82 kW/m 2 and 74.71 MJ/m 2 from 436.66 kW/m 2 and 88.67 MJ/m 2 compared to EVA/MH composites, which may be attributed to the multi-phase synergistic flame retardant mechanism of UPMDM.
危险品化学品经营许可证（带存储）