Comparative study on flame, thermal, and mechanical properties of HDPE/clay nanocomposites with MPP or APP

Abstract

The article reports on flammability, thermal, and mechanical properties of bimodal high-density polyethylene/clay nanocomposites modified with ammonium polyphosphate or melamine polyphosphate (MPP) flame retardants. Two types of clays were used as fillers for the composites—the first one was standard montmorillonite modified with quaternary ammonium salt (ZR2), and the second one was montmorillonite modified with aluminium hydrogen sulfate (ZG1). As a compatibilizer, maleic grafted polyethylene (Plb) was used. X-ray diffraction and transmission electron microscopy were used to characterize the layer structure of clays in the composites. The limiting oxygen index tests showed synergistic effect between both clays and MPP. Flammability was also examined using cone calorimetry technique. The influence of all the fillers on thermal stability (thermogravimetric analysis), crystallinity (differential scanning calorimetry and wide angle X-ray scattering techniques), and mechanical properties was also studied.