Swelling behavior and tensile strength of additively manufactured and commercial O-rings in the presence of linear, branched, cyclic, and aromatic compounds and alcohols

Abstract

O-rings were manufactured using vat photopolymerization additive manufacturing (AM) processes using acrylate and dimethacrylate monomers. Preliminary tests using Flexible 80A and Elastic 50A resin with various printing orientations show that Flexible 80A in the “optimal” orientation is best for printing. Exposure of these O-rings and those from commercial sources to linear, branched, cyclic, and aromatic compounds and alcohols for 24 h causes swelling and changes in the ultimate tensile strength. AM O-rings swell less than the commercially manufactured acrylate O-rings, and their greatest swellings occur with aromatic compounds and the least swellings with linear alkanes. The swelling behavior of commercial O-rings is consistent with reported Hansen solubility parameters. The AM O-ring swelling patterns as a function of Hansen solubility parameters are similar to those of commercial acrylate O-rings. The tensile strength of the unexposed AM O-rings is less than the commercial O-rings and has greater variability. Swelling reduces the ultimate tensile strength of the acrylate O-rings. After evaporation, the tensile strengths of most of the O-rings return to their unexposed values. One major exception is AM O-rings exposed to toluene, where structural damage caused much lower tensile strengths.