Methacrylate-containing polyesters exploited for digital light processing (DLP) are generally prepared through ring-opening polymerization followed by photoactivation via methacrylation, which commonly requires the additional chemical and reaction workup. Herein, such a drawback is overcome by introducing a facile method of sequential addition of ester monomer and glycidyl methacrylate into the reaction. Two different hydroxyl beginning monomers, that is, ethylene glycol and glycerol, were utilized. The chemical structures and molecular weights of the resultant copolymers were analyzed using 1 H-NMR and ATR-FTIR spectroscopy and size exclusion chromatography, respectively. The effects of the copolymer structures on the properties of both resins formulated with and without hydroxyapatite, for example, rheological behavior and printability, and DLP-printed specimens, for example, mechanical property and cytotoxicity, were assessed. By controlling the beginning monomer to monomer feeding ratio from 1:6 to 1:14, the M n values of the resultant copolymers fell in the range of 1.7 to 2.5 kDa. The DLP-printed specimens possessed compressive moduli in the range of 10.20 ± 0.16 MPa and 18.65 ± 0.75 MPa. The cytotoxicity result suggested that the DLPprinted specimens were noncytotoxic to porcine chondrocytes. Altogether, these methacrylate-containing polyesters simply synthesized via a concise one-pot reaction revealed great potential for DLP printing resins in biomedical applications.
K E Y W O R D Scalcium phosphate, composites, cytotoxicity, digital light processing (DLP), mechanical property, poly(ester-co-glycidyl methacrylate), resin formulation
| INTRODUCTIONAdditive manufacturing (AM) is a rapidly developing technology that can precisely build objects layer-by-layer created with computer-aided-design (CAD) programs. 1,2 Recently, significant attention has been paid to the fabrication of biodegradable three-dimensional (3D) porous scaffolds for medical purposes through AM. 3 Several advantages of AM-fabricated scaffolds over conventional process-fabricated scaffolds exist, such as finely controlled architecture and well-defined porous structure favorable for simultaneous tissue regeneration and material degradation and stability. Notably, regulating micro/ nanoscale features is achievable and dependent on the AM technique. 4 In vat photopolymerization, a liquid photopolymer is solidified by light-activated polymerization.
