Stereolithographic 3D printing of pure poly(ether-ester) networks from spirocyclic monomers cationic ring-opening photopolymerization at high temperatures

• Published in: Polymer chemistry Vol. 14; no. 42; pp. 489 - 4818
• Main Authors: Kojic, Danijela, Ehrmann, Katharina, Wolff, Raffael, Mete, Yazgan, Koch, Thomas, Stampfl, Jrgen, Baudis, Stefan, Liska, Robert
• Format: Journal Article
• Published: 31.10.2023
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/d3py00787a

We demonstrate for the first time stereolithographic (SL) printing of pure poly(ether-esters) based on cationic ring-opening photopolymerization without the need to accelerate curing via radical mechanisms. To minimize shrinkage stress in bulk-photopolymer parts, spiro-orthoesters have been utilized as expanding monomers. In combination with a bifunctional spiro-orthoester or epoxide, previously inaccessible pure aliphatic poly(ether-ester) parts have been printed via Hot Lithography, an SL process at elevated temperatures. Precision part size, high resolution and excellent surface-finish could be achieved. During monomer evaluation, the changes in reactivity and polymerization mode of photopolymerization at elevated temperatures were investigated with photo-DSC analysis. Convincing (thermo-)mechanical properties of the cured materials were determined with DMTA and tensile testing. This technological advance gives access to SL manufacturing of a highly regarded material class due to the biocompatibility and biodegradability of aliphatic poly(ether-esters), which frequently find application in medical applications where flexible and highly precise part design is key. We demonstrate stereolithographic 3D printing of pure aliphatic poly(ether esters) from spiro-orthoesters with near-net-zero shrinkage and significantly reduced shrinkage stress.