Study on preparation and properties of epoxy coatings synergistically modified with silicon dioxide and polydimethylsiloxane

In this work, with poly 4-ethylene pyridine (P4VP) as the curing agent and bisphenol A diglycidyl ether (DGEBA) the epoxy monomer, epoxy resin coating of nano SiO₂ (0, 3%, 6%, 12%, massfraction, the same as below) and (0,1%) polydimethylsiloxane (PDMS) were used to synergistically modified epoxy coatings at room temperature. The surface morphology and molecular structure of the prepared coatings were characterized by scanning electron microscopy and fourier transform infrared spectroscopy. The mechanical and tribological properties were characterized using vickers hardness tester and friction wear tester, respectively. FTIR results show that the curing mechanism of epoxy was mainly concerned with the pyridine group from P4VP to induce the ring-opening of the epoxy group of DGEBA. The cointroduction of SiO₂ (3%) and PDMS (1%), which have a marked synergistic effect in improving the anti-friction performance of epoxy resin coating, significantly enhance the mechanical and tribological properties of the epoxy coating. with a friction coefficient as low as 0.045 and a wear rate as low as 5.1×10^-7 mm³/(N·m). However, as the content of SiO₂ nanoparticles increases, the fragility of the coating increases. The tribological performance was optimal when both SiO₂ and PDMS additives are added to the coating and SiO₂ nanoparticles are 3%.