Effect of wood flour content on the flexural properties of mSLA-printed photopolymer composites

Wood flour was used as a bio-based filler for mSLA-printed photopolymer composites to investigate its effect on flexural performance. Pedunculate oak wood flour with a particle size below 100 µm was incorporated into a commercial photocurable resin at 3 wt. % and 9 wt. %, while neat resin served as the reference material. All formulations were printed and post-cured under identical conditions, and flexural behaviour was assessed by the three-point bending method. The 3 wt. % formulation showed the best response, increasing flexural strength by 27 % and flexural modulus by 29 % relative to the neat resin. In contrast, the 9 wt. % formulation reduced both properties. Density increased only slightly with wood flour content, while Weibull analysis showed the highest homogeneity for the 3 wt. % formulation. Overall, low wood flour loading can improve stiffness and strength, as well as reliability in mSLA-printed photopolymer composites, whereas higher loading may be detrimental under the selected processing conditions.