Abstract: In this paper, the microencapsulation of ammonium polyphosphate (APP) was introduced according to the capsule material (melamine, melamine formaldehyde resin, isocyanate polymers, silicone oil and thermoplastic resin). While melamine or melamine formaldehyde resin encapsulation may improve the waterproof and fire retardancy of the APP, silicone oil encapsulation increased its hydrophobicity. When the encapsulated APP was introduced into polypropylene, the fire retardancy of the system was obviously enhanced compared with those based on neat APP.

Key words: ammonium polyphosphate, microencapsulated, polypropylene, fire retardancy