Functionalization of molten polyethylene by ozonization and its application in wood fiber reinforced polyethylene composites

Here we report a fast functionalization method of PE using ozone oxidization to improve the interfacial adhesion between wood fiber (WF) and oxidized PE (OPE) for preparing wood-plastic composites (WPC). Low density PE at molten state was oxidized (at 220 degrees C for 1 h) to form polar groups on molecular chains and further mixed with different content of eucalyptus WF. The effect of ozone on the molecular structure of PE and the properties of WPCs were investigated by FTIR, XPS, contact angle test, rheological test, SEM and mechanical tests. After ozonization, the hydrophilicity of PE was greatly improved due to the introduction of oxygen-containing groups. As a consequence, the interfacial adhesion between OPE and WF was greatly enhanced as a result of hydrophilicity of OPE. The tensile elongation at break of OPE/WF was maximum increased by 65% comparing to PE/WF composites. It is an effective method to improve hydrophilicity of PE, which will provide a feasible route for recycling and utilizing of recycled polyethylene.