Preparation of microcapsulated ammonium polyphosphate, pentaerythritol with glycidyl methacrylate, butyl methacrylate and their synergistic flame‐ retardancy for ethylene vinyl acetate copolymer

A new series of microcapsules containing pentaerythritol (PER) and ammonium polyphosphate (APP) with glycidyl methacrylate and butyl methacrylate as shell materials were synthesized by in situ polymerization. The structure and performance of the microencapsulated APP and microencapsulated PER were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle. The flame retarded ethylene-vinyl acetate copolymer (EVA) composites were studied by limiting oxygen index, UL-94 test, and cone calorimeter. It was found that the microencapsulation of flame retardants (FRs) with the glycidyl methacrylate and butyl methacrylate lead to a decrease in the particle's water solubility and an improvement of the hydrophobicity. Results also demonstrated that the FR properties of EVA/microencapsulated APP/microencapsulated PER composites were better than those of the EVA/APP/PER composites at the same loading of FRs. The thermogravimetric analysis results reflected that the microencapsulated EVA composites had better thermal stability because of the forming of stable char during the combustion. Copyright © 2013 John Wiley & Sons, Ltd.