Synthesis and Characterization of Silicon-Modified Polyurethane Acrylate for UV-Thermal Dual Curing in Three Dimensional Printing

Single UV-curing silicone-modified polyurethane acrylate materials have limitations, such as low molecular polymerization and weak mechanical properties compared to thermal-curing materials. This experiment synthesized a polyurethane prepolymer coated with isocyanate groups using hydroxyl polyether silicone oil (PDMS) and diisocyanate. tert-Butylaminoethyl methacrylate (t-BAEMA) was then utilized to create a silicon-modified polyurethane acrylate (SiBPUA) prepolymer with heat-unstable urea and photosensitive groups. This prepolymer was incorporated into photosensitive resin materials and processed through 3D DLP 3D printing. Upon heating, the −NCO group regenerated, and the chain extender underwent a secondary curing reaction, increasing molecular weight and improving performance. The study investigated the impact of different reactants on SiBPUA properties, deblocking temperature, optimal curing temperature, and enhancement of UV-curing materials through thermal curing. The results revealed that the use of isophorone diisocyanate (IPDI), 4,4′-diaminodicyclohexylmethane (PACM), and methyl methacrylate (MMA) resulted in the best mechanical properties. Furthermore, UV-thermal dual curing significantly enhanced tensile strength (12.5 MPa) and elongation at break (219.5%), broadening the application potential of UV-curing 3D printing materials.