Milled Carbon Microfiber-reinforced Poly(phenylenesulfide) Coatings for Abating Corrosion of Carbon Steel

Effectiveness of milled carbon microfibers, 7.5 μm in diameter and 100-200 μm long, in increasing the thermal conductivity, tensile strength, and elongation of fiber-reinforced poly(phenylenesulfide) (PPS) composite coatings was investigated. Thermal conductivity depended on the fiber content of the composites; the maximum content (5 wt% fiber) was responsible for a 2.6-fold enhancement over that of non-reinforced ones. However, the most effective amount of fiber in improving the tensile strength and elongation of the composition coating films was 3 wt%, reflecting 5.2 times and 2.6 times improvements, respectively, compared with those of the non-reinforced ones. The composite coatings adequately protected the underlying carbon steel against corrosion in 250°C CO₂-laden brine. The reason for their great hydrothermal stability was the conformational changes in the molecular structure of PPS, from sulfide bridging to sulfone bridging, which increased the thermal stability of the matrix.