Maleic Anhydride Grafting onto HDPE by In situ Reactive Extrusion and its Effect on Intercalation and Mechanical Properties of HDPE/Clay Nanocomposites

Nanocomposites based on high-density polyethylene-grafted maleic anhydride (HDPE-g-MA) were prepared by in situ reactive melt mixing using a twin-screw extruder. The effects of different modified clays and maleic anhydride content on intercalation and mechanical properties were studied. The nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy techniques and tensile testing. The results show that clay I.30TC is suitable for preparation of HDPE-g-MA/clay nanocomposites. Grafting HDPE with MA contributed to higher degree of intercalation in clay particles and increases the tensile modulus of nanocomposite. MA content should be maintained at a certain level to improve the extent of intercalation. During the process, grafted maleic anhydride groups on HDPE backbone are converted to acid pendant groups. In order to determine the extent of cross-linking as a function of MA content, the gel content of the samples were measured. A significant improvement in the tensile modulus of the HDPE/clay nanocomposites was observed without changes in tensile strength and elongation-at-break values.