EFFECTS OF CARBON FIBER LOADING ON THE CONDUCTIVE, MECHANICAL, EMI SHIELDING EFFECTIVENESS PROPERTIES OF MICROCELLULAR FOAMS OF PBT/CARBON FIBER COMPOSITES

摘要

This study investigated the carbon fiber loading on the mechanical/electrical conductivity/EMI shielding effectiveness properties of Polybutyele Terephthalate(PBT)/carbon fiber composites. The PBT/carbon fiber composites were compounded by twin-screw extruder as a master batch of 13 wt.% . Then composites were diluted into 1, 3, 5, 8, and 13wt% during the injection molding process. The results showed as the carbon fiber loading increased so is the tensile strength. It level off at the carbon fiber loading of 8wt. %. The conductivity test showed that as the carbon fiber loading increased so is the conductivity. And conductivity test were done at 3 different locations (surface, 0.3 mm under surface, and 1.5 mm under surface). For the different positions, the conductivity showed as the position is far from surface the conductivity increased. For the carbon fiber distribution, SEM results showed that there are more fibers on the PBT matrix when the location is far from sample surface. For the electromagnetic interference (EMI) shielding effectiveness(SE), the EMI SE for carbon fiber loading less than 13 wt% is almost zero. So the carbon fiber loading is increased to 20, 25, and 30 wt.% respectively. As the carbon fiber loading is increased from 20 ~ 30 wt%, so is the EMI SE value.