Down-conversion particles as internal UV-source assist in UV-curing systems: Physical and mechanical properties of UV-curable micro-composites

UV-curable composites always suffer from low conversion due to the low penetration depth of photons as a result of absorption of light by fillers. Herein, down-conversion particles were introduced as mineral materials within the composites to observe the alteration in final conversion along with some physical and mechanical properties. FT-IR, DMTA, micro-indentation, pendulum hardness, scratch resistance, and surface roughness analysis exhibited no reduction in the photopolymerization process in all the composites, and enhanced scratch resistance up to 5% filling. Storage modulus and cross-linked density were increased up to 5% loading, and enhanced micro-hardness up to 5% loading and decreased in 10% loaded composites. However, the surface hardness decreased because of increased surface roughness due to the addition of micron-sized fillers.