Polyurethane, Polyurea and Urethane-Acrylate Photopolymers for Vat Photopolymerisation: Chemical Identity, Segment Architecture, Hydrogen Bonding, Hydrolysis and Qualification

Urethane- and urea-containing photopolymers occupy a large design space between low-viscosity printing resins, soft elastomers and highly crosslinked thermosets. Primary studies demonstrate flexible urethane-acrylate elastomers, multiple-hydrogen-bond poly(urethane–urea) networks, non-isocyanate acrylic polyhydroxy urethanes, dual-curable polyurethane acrylates and urea-containing photocurable monomers. These examples show that segment selection, reactive functionality, association, chain extension and post-cure can alter modulus, extension, toughness, swelling and print resolution. They do not establish a universal polyurethane property envelope. Chemical naming must identify the load-bearing network and the reaction that creates it: an acrylate-cured urethane oligomer, a step-growth polyurethane, a polyurea-containing network and a non-isocyanate polyhydroxy urethane are not equivalent structures. Hydrogen bonding can raise cohesion and dissipate energy, yet association is sensitive to temperature, water, competing solvents, conversion and morphology. Ester-bearing soft segments or pendant groups can introduce hydrolysis-sensitive sites, whereas ether-rich architectures create a different ageing balance; exact retention remains formulation- and state-specific. A defensible qualification programme therefore combines identity, conversion and extraction evidence with tensile and dynamic-mechanical response, water uptake, liquid exposure, thermal analysis, accelerated ageing and component-representative retained properties. This paper supplies that architecture without disclosing a proprietary formulation, ranking commercial materials or granting intended-use approval.

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