Preparation and flame retardance of polyethylene composites with microencapsulated resorcinol bis(diphenyl phosphate), red phosphorus and magnesium hydroxide

Polyethylene (PE) modification to have flame retardant and anti-dripping capabilities is indispensable for public safety and environmental protection. To the end, PE modification with flame retardant resorcinol bis(diphenyl phosphate) (RDP) is suggested but a poor compatibility of PE with RDP is problematic. In this work, a microencapsulation of RDP using melamine-urea-formalin resin as shell material was proposed to resolve the compatibility problem, making PE composites with microencapsulated RDP (MCRDP), red phosphorus (MCRP) and magnesium hydroxide (MH). Through the material characterization, it was found that the spherical MCRDP particles were fabricated in homogeneous distribution of particle sizes. The flame retardance of the PE composite samples with different compositions was tested according to the UL-94 method, finding that the PE/20%MCRDP/5%MCRP/5%MH composite has the best performance. Moreover, the thermogravimetric analysis showed that this composite exhibited higher decomposition temperature than pure PE and PE/30%MCRDP composite, revealing the P-N synergy effect on improving the flame retardance of PE composites.