Dithiolane and Lipoate Photoresins for Vat Photopolymerisation: Ring-Opening Disulfide Networks, Dynamic Exchange, Depolymerisation, Reprinting and Qualification

Dithiolane and lipoate photoresins replace or supplement conventional carbon-carbon-forming vinyl cure with light-driven ring opening of strained cyclic disulfides. The resulting linear disulfides can exchange, relax stress and, under controlled dilution, heat or catalytic conditions, revert toward cyclic monomer. Direct evidence now spans 405 nm DLP, commercial LCD printing and two-photon lithography. Renewably sourced lipoate mixtures have been printed, depolymerised and reprinted across two recovery cycles; tetrafunctional dithiolanes have shown approximately 95% monomer mass recovery; and latent-base formulations provide thermally triggered depolymerisation at macro- and microscales. A separate acrylate/lipoate strategy embeds dynamic disulfides in a conventional vinyl network, so its cleavage and reprinting route cannot be equated with direct polydisulfide ring-opening polymerisation. Reversibility creates liabilities as well as opportunities: concentrated monomers may gel during storage, solvent or base can govern the apparent loop, initiator fragments and oligomers can accumulate, and dynamic exchange can limit thermal service. ER-111 supplies an identity-, equilibrium- and mass-balance-resolved qualification architecture for cure, retained use, depolymerisation and reprinting.

3Dresyns Engineering Review ER-111, version 0.2. Provider-neutral technical review. The deposited PDF is controlled by its exact SHA-256 in the release manifest.