Mechanical and electrical properties of short carbon fibre reinforced polycarbonate composites
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Date
2018-06
Authors
Yap, Cia Ling
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Abstract
A series of composites was prepared using polycarbonate (PC) as the matrix, reinforced
with short carbon fibre (SCF) at different weight fractions. The composites were
compounded by single screw extruder and specimens were prepared by injection
moulding machine. The effect of fibre weight fractions on the mechanical and electrical
properties of SCF reinforced polycarbonate composite was studied. The test specimens
were fabricated in accordance to the ASTM specifications. The mechanical properties of
the composites were characterized by tensile, flexural and fracture toughness tests,
while the morphological properties were characterized by scanning electron microscope
(SEM). In addition, electrical properties were evaluated by surface resistivity test. Cox Krenchel and rule of mixtures (RoM) were used to predict theoretical tensile moduli of
the composites. Experiment results revealed that density of the composites increased
with the addition of SCF. Fibre length was found to be greatly reduced during processing
the of composites. Higher mean fibre length tends to provide better reinforcement effect,
thus enhanced mechanical properties. Incorporation of SCF improved the strength of the
composite, and the effect was more prominent at higher weight fraction of SCF. With
increasing SCF content, the surface resistivity reduced drastically with the percolation
threshold lie in between 10% - 14% of SCF weight fraction. Cox-Krenchel model showed
to be a good approximation to predict the composites’ tensile modulus. 14% SCF
reinforced PC composite which was obtained from commercial compound proved the
effective extrusion compounding of these self-compounded composites (5%, 10% and
15% SCF), by possessing intermediate properties in between 10% and 15% SCF
reinforced PC composites as expected.