Characterization of Microcellular Foamed PVC/Cellulosic-Fibre Composites

A microcellular plastic is a foamed polymer of a cell size in the range of 0.1 to 10 μm and a cell density in the range of 109 to 1015 cells/cm3. Typically, microcellular plastics have been shown to possess superior impact strength, toughness, and fatigue life to solid polymers. Polymer/cellulosic-fibre composites make use of cellulosic-fibres as a reinforcing filler in the polymer matrix and are known to be advantageous over the neat polymers in terms of the material cost and some mechanical properties such as stiffness and specific strength. These polymer/cellulosic-fibre composites are microcellular processed to create a new class of materials with unique properties. In this paper, the feasibility of the production of microcellular PVC/cellulosic-fibre composites and the effect of the fibre content on the cell morphology are studied. Particular emphasis is given to the fibre surface treatment to investigate its effect on the microcellular morphology. Each step of microcellular PVC/cellulosic-fibre composite processing is addressed including the treatment of the cellulosic-fibre surface, the manufacture of the composite by the mixing of PVC and cellulosic-fibre, the saturation of the composite with gas, and the bubble nucleation and growth. The preliminary experimental results indicate that the surface modification of cellulosic-fibre plays a strong role in determining the interface between the polymer and fibre as well as the cellular morphology of the foamed composites.