Journal of Applied Polymer Science, EarlyView.

A new type of flame retardant (MH‐WD70‐DOPO) was prepared by combining surface modification of magnesium hydroxide (MH) with synergistic flame retardant effect of DOPO. First, DOPO‐WD70 was prepared by the free radical reaction between DOPO and WD70. Then, the hydroxyl groups on the surface of MH can react with the –Si‐OR in DOPO‐WD70 to produce MH‐WD70‐DOPO. Finally, we filled MH‐WD70‐DOPO into EVA to explore the effect of modified MH on the performance of EVA.

Abstract

Magnesium hydroxide (MH) nanoparticles have been considered as an excellent nonhalogen flame‐retardant. However, the drawbacks of easy aggregation and relatively low flame retardancy limit their applications in polymer materials. In this research, MH nanoparticles were successfully grafted by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) through the bridge of vinyl silane coupling agents (WD70). The grafted MH nanoparticles (MH‐WD70‐DOPO) were characterized by Fourier transform infrared spectra, ³¹P nuclear magnetic resonance spectra, thermogravimetric analysis, transmission electron microscopy, and X‐ray photoelectron spectroscopy spectra. MH‐WD70‐DOPO nanoparticles were incorporated into ethylene‐vinyl acetate copolymer (EVA) matrix by melt blending method. The results indicated that MH‐WD70‐DOPO nanoparticles were much homogenously dispersed in EVA matrix than unmodified MH particles. EVA/MH‐WD70‐DOPO nanocomposites with 51.32 wt% loading showed higher flame retardancy, better mechanical and processing properties compared with EVA/MH‐WD70 sample. These findings could provide a novel method to enhance the flame‐retardant efficiency of inorganic hydroxide flame retardants, while keeping good mechanical and processing properties of polymer materials.