Thermal and flammability properties of polyethylene composites with fibers to replace natural wood

Composites of high-density polyethylene and lignocellulosic fiber residues from banana, papaya, and peach palm trees, in addition to sponge gourd and coconut fiber, were investigated to identify the least flammable composite as a potential substitute for natural pine wood. The high-density polyethylene/lignocellulosic fiber composites were prepared in a twin-screw extruder, injection molded to obtain specimens, and characterized in terms of thermogravimetry, flammability using the UL-94 burning test and limiting oxygen index, impact resistance and heat deflection temperature. The high-density polyethylene/sponge gourd fiber composite showed the best impact resistance and was selected for further tests, with the addition of 10wt% magnesium hydroxide and (or) rice husk ash as flame retardants. The use of both retardants provided greater thermal stability to the composite. The addition of magnesium hydroxide to the high-density polyethylene/sponge gourd fiber composite improved the flammability properties of horizontal burning and thermal stability and is a potential candidate to replace natural wood.