Influence of co‐monomer‐type and amount on thermomechanical properties of ultrafast‐curing acrylic resins using a triacrylic crosslinker

ABSTRACT An ultrafast ultraviolet‐light‐cured acrylic resin was developed. The monoacrylic monomers ethylene‐glycol‐phenyl‐ether acrylate (EGPEA), 2‐hydroxy‐3‐phenoxypropyl acrylate (HPPA), di(ethyleneglycol)‐ethyl‐ether acrylate (DEGEEA), or poly(ethyleneglycol)‐phenyl‐ether acrylate (PolyEGPEA) were each mixed with varying amounts of the triacrylic crosslinker tris[2‐(acryloyloxy)ethyl] isocyanurate (ICTA). The curing time was 1 s at room temperature (average degrees of curing between 55 and 85%). The specimens of ICTA‐EGPEA showed a maximum tensile strength of 76.0 ± 1.4 MPa, an E‐modulus of 4216 ± 188 MPa, an elongation at break of 2.3 ± 0.1%, and a glass transition temperature ( T g ) of 100 °C. The development of properties with increasing amount of crosslinker could be well described on the basis of percolation theory. Below the percolation threshold the behavior is dominated by the auxiliary co‐monomer. Above the percolation threshold the behavior is dominated by ICTA. On exchanging EGPEA by HPPA, the influence of hydrogen bonding on the thermomechanical properties was extracted. Exchanging EGPEA by DEGEEA or PolyEGPEA allowed for exploring the influence of beta‐relaxation of the monoacrylic monomers on the thermomechanical properties of the resin. Large ester side‐groups reduced the tensile strength, the E‐modulus, and the T g decisively. The impact strength in turn was decisively increased using PolyEGPEA as auxiliary co‐monomer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47294.