Abstract: This article discussed the research development on the relationship between structure/morphology and properties of PE-HD/clay nanocomposites. It was found that organic treatment of clay and the addition of compatibilizer improved the “intercalation” and “exfoliation” structures of the nanocomposites. The influence of the molecular weight of PE-HD on the nanocomposite’s structure was in two aspects: (i) the larger the size of molecular chain, the more difficult for it to intercalate into the interlayer of clays; (ii) the higher the viscosity resulted from the high molecular weight, the larger the shearing force could be imposed to promote the intercalation or exfoliation. High content of clay was not favorable for the exfoliation. For the processing conditions, the masterbatch method was better than the single pass method, and a higher exfoliation fraction could, the toughness reduced with increasing content of clay. The clay layer constituted a two-dimensional nucleation surface, which increased the crystallization temperature and rate, however, the presence of clay may reduce the degree of crystallinity. An exfoliation structure was necessary for good barrier properties, which was positive for enhancing the thermal stability, however, the organic modifier and the catalysis action of clay may increase the degradation of polyethylene. In addition, due to the formation of a clay-enriched protective char during combustion, the flame retarding property of the nanocomposite was improved.

Key words: high density polyethylene, clay, nanocomposite, structure, property