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This paper presents the foaming behaviors of high-density polyethylene (HDPE)-based and polypropylene (PP)-based wood fiber composites with a small amount of nanosized clay. Melt compounding was used to prepare various types of clay-filled, wood fiber composites, such as intercalated and exfoliated clay composites. Their morphology was determined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The extrusion foaming was conducted using N2 as the blowing agent. The cell nucleation and growth behaviors of composite foams were studied while varying temperature, pressure, wood fiber content, and clay content. The effects of clay content and exfoliation degree on the final cell morphology of wood fiber/polyolefin/clay nanocomposite foams were identified.

This research presents a fundamental study of the interaction between chemically modified wood fibers and high density polyethylene (HDPE) to develop wood fiber/HDPE composites with satisfactory performance. This paper investigates the effects of the interfacial properties of HDPE and wood fibers on the rheological properties and foaming behavior of the composites. The surface characteristics of wood fiber were modified by treating the fiber with trialkoxy silane. The effectiveness of chemical surface modifications of wood fiber was characterized using FT-IR. The effect of the interfacial interaction on the foaming behavior was studied via extrusion foaming with a physical blowing agent. The rheological property of the composites with a different interfacial structure were also evaluated by using dynamic oscillatory rheometer.

This study compared the mechanical properties of rice hull/high density polyethylene composites with those of maple wood-based counterparts. In addition, the effects of maleated polymers on the mechanical properties of rice hull and maple wood composites were investigated. Six types of maleated polymers (coupling agents) were used to improve mechanical properties, of the composites, especially notched Izod impact strength. The results suggested that the maple wood composites showed higher strength, modulus and impact strength than the rice hull composites. The results also indicated that maleated thermoplastic elastomers increased notched Izod impact strength of both composites dramatically. However, it was found that Maleated metallocene polyethylene was the most effective coupling agent that increased notched impact strength without sacrificing tensile and flexural strength.

This research investigated the intercalation and exfoliation behaviors of polypropylene (PP)/clay nanocomposites. Different samples were prepared by melt blending with various combinations of PP, maleic anhydride grafted PP (PP-g-MAn), and nano-clay. The effects of key processing variables such as the mixing time, mixing temperature and screw rpm were investigated from the thermodynamic and kinetic point of view. The morphology was determined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Effective strategies for controlling intercalation and exfoliation of PP/clay nanocomposites are proposed and evaluated.

This research investigates the foaming behaviors of polypropylene (PP) and PP/clay nanocomposites blown with supercritical CO2. In this context, special attention is paid to the effects of varied clay content on the foamed structures. First, a master batch of nanocomposites with 1% and 5% clay are prepared; the nanocomposites are then characterized using X-Ray Diffraction (XRD) prior to and after their subjection to the foaming process. Subsequently, foaming experiments are conducted using supercritical CO2 as a blowing agent. The cell nucleation and expansion behaviors of the PP-based nanocomposite foams are studied at various clay contents and die temperatures. Finally, the effects of the clay content on the cell morphology, the cell density, and the expansion ratio of the PP/clay nanocomposite foams are identified.

This paper demonstrates the effects of nano-clay on the microcellular foam processing of nylon. First, Nylon 6 nanocomposites with 1 wt% clay were prepared by a twin screw extruder. The nanocomposite structures were characterized by XRD and TEM. Nylon and its nanocomposites were foamed in extrusion using CO2. The cell morphologies of nylon and its nanocomposite foams were investigated. It appeared that the nano-clay not only enhanced cell nucleation, but also suppressed cell deterioration in the microcellular foaming of nylon.