X-ray Photoelectron Spectroscopy Study of the Ammonium Polyphosphate-Pplyurethane System used as Fire-retardant Additive in EVA

摘要

First, the efficiency of a mixture PU/APP as fire retardant in an ethylene-vinyl acetate matrix is investigated. It is shown that the fire performance is sharply improved. Second, the mechanism of fire retardancy of PU/APP is discussed considering the protective surface material, investigated by X-ray photoelectron spectroscopy. It is shown that APP contributes to the formation of the intumescent shield creating stable nitrogenated as well as phosphorus compounds via reaction with PU and/or with its degradation products. Such species modifies the mechanical properties of the shield resulting in an improvement of its fire retarding properties.