Core/Shell PBA/PMMA-PGMA Nanoparticles to Enhance the Impact Resistance of UV-Cured Epoxy Systems

Crosslinked core/shell PBA/PMMA-PGMA particles are prepared by emulsion polymerization and dispersed into a UV-curable cycloaliphatic epoxy resin in the range of 515?wt%. The presence of the particles does not significantly affect the UV curing process: a slight decrease of final epoxy group conversion is attributed to an increase in the viscosity when CS-GMA is added to the photocurable formulation and to an enhanced vitrification effect. The presence of the particles does not modify the Tg of the cured materials, while an enhancement of impact resistance is observed that does not depend on the particle content. FESEM micrographs for epoxy reinforced with core/shell particles indicate a plastic void growth of the epoxy polymer and shear yielding toughening mechanism.