Characterisation and evaluation of nano gelcoat degradations in marine environment

Nanotechnology has been extensively explored and exploited for developing functional and smart coating systems with significant performance enhancement. In this context, a development of novel characterisation methodology for surface quality evaluation of diverse coating systems at nano and micro scales has great importance and significance. In this study, nano particles were introduced into conventional gelcoat system in an attempt to achieve improved coating quality and enhanced anti-blistering performance. Accelerated gelcoat ageing in a marine environment was carried out by maintaining constant contact with water using a purpose built jig at 65 degrees C. The progressive ageing of samples has been monitored and evaluated by visual observation, nano-indention test, surface roughness and profile measurement. It was observed that the addition of nano-clays led to an increase in hardness. Although the ageing of various coating systems resulted in a reduction in hardness, the degree of hardness change due to ageing for all nano-coating was significantly less than for coating system without nano-clays. The coating degradations were further characterised by reduced surface homogeneity in terms of standard deviations of hardness. The accelerated ageing induced coating degradations were also quantified by surface profile and roughness measurement in which a stylus profilometer was employed to scan different locations of the coatings. It showed significant differences in surface roughness of different coatings systems and incremental degradations as a function of ageing durations. It has demonstrated that anti-blistering gelcoat systems can be developed by introducing chemically modified nano-clays into conventional gelcoat systems for marine applications.