Utilisation of ultrasound technology on carbon fibre reinforced polymer to mitigate marine biofouling

The structural impact of a commercial ultrasound technology system on carbon fibre reinforced polymer (CFRP) was studied. The system is used to minimise biofouling on marine vehicles and CFRP is slowly being introduced as a structural material in marine vehicles. Initial results from physico-chemical and mechanical tests on CFRP exposed to a period of uninterrupted ultrasonic waves is presented here. Results suggest that ultrasonic waves, under the conditions of 30 days exposure to a pre-set wave pattern in the frequency range of 18-42 kHz, induces not only surface chemical changes but also structural changes to CFRP. Surface chemistry changes were derived from Raman spectroscopy and water contact angle measurements and, structural changes derived from short-beam shear (ASTM D2344) and flexural (ASTM D7264) testing. When compared to non-exposed CFRP, exposed CFRP demonstrated to be less hydrophilic (15.90 ± 12.23%) along with less short-beam strength (21.84 ± 8.53%) and less stiffness (25.27 ± 2.50%). In fact, the differences between non-exposed CFRP (Day 0 - CFRP control sample) and exposed CFRP (Day 30 - CFRP exposed test sample) were statistically significant data for water contact angle, short-beam shear and flexural testing methods, P=0.0179, P=0.0215 and P=0.0006, respectively.