Hemiacetal-Ester and N,O-Acetal Photoresins for Vat Photopolymerisation: Acid-Triggered De-crosslinking, Hydrolysis, Reprocessing, Polymer Recovery and Qualification

Hemiacetal-ester (HAE) and N,O-acetal junctions offer two routes to degradable VPP thermosets. HAE-terminated polyurethanes use methacrylate cure for geometry and dilute acid to release a reusable polyurethane diol after poly(methacrylic acid) removal. Oxazolidone N,O-acetals use thiol–ene cure; their exchange and hydrolysis depend on protic species, temperature, base, dynamic-bond fraction and topology. Direct evidence includes CLIP printing, vat working curves, 50 µm layers, acid dissolution, hot-press reprocessing and measured mechanical loss. O,O-acetals, ketals, HAE and N,O-acetals are not interchangeable, and dissolution, recovered polymer, reprocessing and monomer recovery are different endpoints.

3Dresyns Engineering Review ER-113, version 0.2. Provider-neutral technical review. The deposited PDF is controlled by its exact SHA-256 in the release manifest.