Abstract: Encapsulated ammonium polyphosphate coated with melamine-formaldehyde resin (MFAPP) was prepared by in situ polymerization, and characterized by SEM and TGA. Water resisting properties and flame retardant properties of MFAPP and Dipentaerythritol (DPER) in SEBS were also studied. SEM results confirmed that APP could be finely encapsulated. The weight loss of MFAPP between 50 ℃ and 250 ℃ was only 1.629 %, which indicated well thermal stabilities. Samples of SEBS/ MFAPP/DPER composites did not turn white in hygrothermal condition for 4 days, which exhibited much better water resisting properties than samples of SEBS/APP/DPER composites. When using MFAPP and DPER as intumescent flame retardant (IFR), 30 % fill amount was enough to reach FV-0 level without decreasing mechanical properties.

Key words: hydrogenated styrene-butadiene-styrene bolck copolymer, ammonium polyphosphate, encapsulation, thermal stability, flame retardancy, water resisting property, mechanical property