Yoon H. Lee1, Takashi Kuboki2, Chul B. Park2, and Mohini Sain1. (1) Center for Biocomposites and Biomaterials Processing, Faculty of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada, (2) Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada
The paper investigated the effect of clay on extrusion foaming of polypropylene (PP)/clay composites and wood fiber (WF)/PP/clay composites that contained a small amount of clay, up to 5 wt%. The composites were prepared by a melt blending masterbatch process. The clay dispersion in the composites was characterized by a X-ray diffractometer while the viscosity of the composites was evaluated by a rotational rheometer. The foaming behaviour of the composites was examined using an extrusion foaming system, in which N2 was used for foams as a physical blowing agent. The results suggested that the organoclay provided higher cell density for PP/clay composites than the natural clay, and the addition of organoclay was more effective in improving the cell morphology (decrease of cell size and more uniform cell size) for the WF/PP/clay composites with lower fiber loading.