The Polymer Society of Korea

박세원 (중앙대학교)

이종휘 (중앙대학교)

Cellulose is hard to dissolve and reprocess because strong hydrogen bonding maintains high crystallinity. Here, cellulose-rich spent coffee grounds (SCG) were made processable by simple ball milling, without dissolution or derivatization. Milling reduced crystallinity and broke particulate morphology into rough and fibrous particles. Ball-milled SCG was blended with natural urushiol-based lacquer to form a slurry governed by physical interactions (mechanical interlocking and other non-covalent forces). The slurry showed shear-thinning and thixotropy, enabling stable extrusion and shape retention. Using extrusion-based 3D printing, structures with varied geometries were fabricated. After urushiol infiltrated interparticle voids, curing oxidatively polymerized, producing a continuous network. This work indicates that mechanical processing can bypass cellulose’s processing limits and support biomass-waste-based sustainable composites.