Influence of vermiculite addition on particleboard properties with varied urea formaldehyde adhesive ratios

Wood and wood-based panels are widely used in the construction and furniture industries; however, their inherently low fire resistance remains a major limitation. Vermiculite, a mineral that expands significantly at high temperatures, offers a promising solution to improve the fire resistance of such materials. This study aims to determine how varying vermiculite contents (0 %, 15 %, 20 %, 25 %) and urea–formaldehyde (UF) adhesive levels (12 %, 14 %, 16 %) jointly influence the physical, mechanical, and thermal performance of particleboards. Single-layer panels were manufactured under controlled pressing conditions, and their dimensional stability, strength properties, and thermal behavior were evaluated. Increasing vermiculite content led to higher thickness swelling and water absorption; for instance, at 25 % vermiculite, 2 h TS rose to 45.7 % in the 12 % UF group, while increasing UF to 16 % reduced this value to 31.4 %. Mechanical performance decreased with vermiculite addition: MOR declined from 15.77 MPa (control) to values below P1 requirements at higher vermiculite ratios, although increased UF partially mitigated this loss. In contrast, thermal properties improved markedly; mass loss during TGA decreased from 91.34 % (control) to 72.55 % at 25 % vermiculite with 16 % UF, indicating enhanced resistance to thermal degradation. These findings demonstrate that vermiculite substantially enhances thermal stability but compromises mechanical integrity, underscoring the need for careful balance between mineral content and adhesive level. Optimized vermiculite–UF combinations can support the development of particleboards for fire-resistant interior applications, offering valuable guidance for future material design and industrial implementation.