Thermal and Mechanical Properties of Zeolite Filled Ethylene Vinyl Acetate Composites

Ethylene vinyl acetate (EVA) composites filled with zeolite (25 vol.%) were prepared using an internal mixer followed by compression molding machine. In order to enhance the thermal properties and fire retardancy of the composites, an intumescent flame retardant consisting of ammonium polyphosphate (APP)/pentaerythritol (PER) was incorporated into the composites. Two kinds of flame retardants were used which are untreated APP (APP1) and silane treated APP (APP2), where their effectiveness was evaluated by means of differential scanning calorimetry (DSC) and also thermogravimetric analysis (TGA). The results showed that both types of flame retardants have the ability to enhance the thermal stability of EVA/zeolite composites by producing charred layer which protects the underlying composites from the action of flame. Moreover, the incorporation of APP1 and APP2 has a significant effect on the composites degree of crystallinity. Meanwhile the results of tensile testing showed that the composites with APP2/PER exhibit better tensile properties compared to that with APP1/PER. This is expected since the application of silane-treated APP (APP2) could improve the dispersion of APP particles within EVA matrix. (C) 2012 Published by Elsevier Ltd.