Assessing chemical, physical, biological and mechanical properties of contact surface thermal treated glubam

This study investigated the effects of contact surface thermal treatment on the physical, chemical, mechanical, and biological properties of glued-laminated bamboo (glubam), an engineered bamboo material fabricated by laminating five thick bamboo strips with resorcinol-formaldehyde (RF) adhesive. The contact surface thermal treated glubam was prepared using an electrically heated metallic table at temperatures of 190°C, 230°C, and 270°C. XPS and FTIR analyses identified a reduction in the oxygen-to-carbon ratio, indicating hemicellulose degradation, lignin condensation, and the formation of a carbon-enriched surface. Physical assessments demonstrated a substantial reduction in surface wettability, with water contact angles increasing from 13.3° for the untreated specimen to 121.1° for the specimens treated at 270°C. Fungal attack (Aspergillus niger) tests for 56 days revealed that the contact surface thermal treatment reduced surface attack colonization and discoloration. Compression tests showed that 190°C and 230°C treatments improved the mechanical performance, while treatment at 270°C induced micro-cracking and debonding. Although 230 and 270°C effectively reduced fungal discoloration, the 190°C treatment retained the highest compression strength and modulus after fungal attack, providing the best balance between fungal resistance and mechanical integrity for structural glubam applications.