The use of shellac as wood adhesiveBrus, Maks (Avtor) Šernek, Milan (Mentor) Jones, Dennis (Komentor) shellacbio-based adhesivenatural adhesivewood bondingthermal curinghot pressingcold pressingABESFTIRDSCTGAbond strengthShellac is a natural biopolymer, and traditionally it has been used in coatings and food packaging, with little scientific study of its application as a wood adhesive. This study explored shellac adhesive properties and optimized pressing conditions. Six different shellacs were examined with cold pressing with bond values between 7.5 and 9.5 MPa; SH2 (platinum shellac) was selected for more detailed examination. Thermal treatment improved stability: curing at 175 °C for 60 min increased Tg from 42 °C to 77 °C and reduced mass loss at 200 °C from 1.55 % to 0.47 %. FTIR confirmed crosslinking with reduced hydroxyl content and increased ester bands. Modelling of shear strength formation with ABES showed good fit with Hill model (R2 = 0.971) and moderate fit with Logistic model (R2 = 0.875). Hot pressing at 175 °C and 200 °C yielded 9.78 MPa and 8.2 MPa under dry conditions (D1), and 3 MPa and 8.4 MPa under occasional moisture conditions (D2), respectively. However, 200 °C pressing temperatures resulted in wood degradation with nearly 100 % wood failure. Shellac has potential for application as a bio-based adhesive, particularly in cold-pressing, and niche water free bonding, but optimization is required to improve moisture resistance and to prevent wood modification in hot pressing.[M. Brus]20252025-09-17 07:16:18Magistrsko delo/naloga173372sl