Microencapsulation of hydrophilic solid powder as a flame retardant with epoxy resin by using interfacial reaction method

Microencapsulation of Bistetrazol · diammonium (BHT · 2NH₃) as a hydrophilic powdery flame retardant was tried by the interfacial reaction method in reverse emulsion. In this microencapsulation method, water droplets containing BHT · 2NH₃ and hydrazine as gelation agent for epoxy resin were dispersed in the continuous phase of corn oil. When epoxy resin was added to the continuous phase, BHT · 2NH₃ as a core material was microencapsulated by the reaction of epoxy resin with hydrazine on the interface between the surface of water droplet and the continuous phase. The content of the core material from 70 to 85%, and the microencapsulation efficiency from 89 to ca 100% were able to be attained under the experimental conditions adopted here. Copyright © 2009 John Wiley & Sons, Ltd.