Abstract
To enhance the thermal conductivity and improve the mechanical properties of poly(phenylene sulphide) (PPS) that was used as a coating for carbon steel heat exchanger tubes, chopped carbon fibres, ∼7.5 μm diam. x ∼3 mm long were incorporated into the PPS matrix. All the experiments in this work were performed using steel panels instead of steel tubes. As a result, 0.5 wt% of fibres was the most effective amount of fibres in minimizing the rate of penetration of electrolytes through the composite coating films. Even though the steel panels coated with the 0.5 wt% fibre-reinforced PPS composites were exposed for 14 days in an autoclave containing 20,000 ppm CO2-laden 13 wt% NaCl solution at 200°C, the coatings remained intact. This suggested that the composite coatings not only adequately protect steel against corrosion in a wet, harsh, and hostile geothermal environment, but they also have great hydrothermal stability. In addition, the thermal conductivity of the bulk PPS rose ∼ 60% by adding 0.5 wt% fibre. The rough surface texture of the fibres provided good mechanical interlocking bonds with the PPS matrix. Such interfacial bonding can be interpreted as one of the factors governing the outstanding mechanical properties, such as tensile strength, tensile modulus, and elongation, of the multidirectional fibre-reinforced composite films.