SURFACE WEAR OF MODIFIED GELCOATS USED IN THE MARINE INDUSTRY

<ns3:p>Gelcoats are polymer matrix composites (PMCs) based on epoxy, vinyl ester, and unsaturated polyester resins, commonly used as coatings for boat hulls, cockpit soles, patrol boats, minesweepers, and submarine domes. These applications demand structural stability and high performance of composites in seawater. The gelcoat is the component directly exposed to the external environment, and its durability depends on the surface properties, which can influence the overall strength of the hull. The study was conducted on three types of gelcoats: unmodified; with the addition of halloysite nanoparticles; and with both halloysite nanoparticles and graphene flakes, with a dimension of at least one particle not exceeding 100 nm. To determine their surface properties, microscopic observations were carried out using a scanning electron microscope (SEM, JEOL JSM-7800 F, Japan). Surface roughness was measured with a Hommel Etamic T8000 profilometer, and the contact angle was examined with a KSV goniometer. Tribological wear tests were performed on a PT-33 tribometer under specific operating conditions. After completing the tribological tests, the changes in tribological parameters – such as the coefficient of friction and abrasive wear on the surfaces of the tested materials – were analysed. The results obtained do not show significant changes in the surface properties ofmodified gelcoats or in the characteristics of their tribological wear. However, the addition of enhancement agents in the form of halloysite and graphene flakes influenced the nature of damage in the tested materials.</ns3:p>