Evaluation of novel urethane dimethacrylates as crosslinkers for the development of fracture tough dental materials containing a poly(ε‐caprolactone)‐polydimethylsiloxane‐poly(ε‐caprolactone) triblock copolymer

Abstract

AbstractPhotocuring 3D printing of materials exhibiting high fracture toughness and excellent mechanical properties (flexural strength/modulus) is challenging. Nowadays, most of the photocurable 3D printing resins are based on a mixture of multifunctional (meth)acrylates and provide therefore brittle materials. This article describes further developments of a toughening strategy based on the incorporation of block copolymers in low crosslink density methacrylate‐based materials. Six dimethacrylates bearing a bisphenol A core and urethane groups are successfully synthesized. Various spacers between the bisphenol A core and the methacrylate groups are selected. Each monomer is combined with (octahydro‐4,7‐methano‐1H‐indenyl)methyl acrylate as a monofunctional monomer and a poly(ε‐caprolactone)‐polydimethylsiloxane‐poly(ε‐caprolactone) triblock copolymer is added as toughener. It is shown that the addition of the triblock copolymer results for all mixtures in a strong increase of the fracture toughness. Moreover, the higher the amount of monofunctional monomer, the stronger the increase. The nature of the urethane dimethacrylate is found to have a significant influence on the fracture toughness, flexural strength, and flexural modulus of cured materials. Two of the synthesized dimethacrylates are identified as promising candidates for the development of fracture‐tough photocuring 3D printing materials.