Effect of Tobacco Stalk Additive Particle Size on the Bond Strength and Formaldehyde Emission of Urea Formaldehyde Bonded Plywood

Abstract

The study investigated the use of native type (Batek) tobacco (Nicotiana tabacum L.) stalk particles from two different mesh sizes – passing 100 mesh but retained at 200 mesh coded as N-100m (74–149 µm) and passing 200 mesh coded as N-200m (< 74 µm) – as additive with both extender and filler property, as well as formaldehyde scavenging property in urea-formaldehyde (UF) resins adhesive formulation used to bond veneers [Falcataria moluccana (Miq.) Barneby & J.W. Grimes] into plywood. The effect of tobacco stalk particle (TSP) size on adhesion performance, tensile shear strength (TSS), and wood failure (wF), as well as formaldehyde emission (FE) of three-ply plywood, was investigated and compared with traditional additives such as wheat flour (WF), coconut shell flour (CS), and rice hull flour (RH). The glue-mix containing UF resins with TSP at 8% by mass was blended very well. There is no difference in the TSS and wF of plywood bonded with N-200m TSP as additive compared to commercial UF formulations; however, a significant decrease of TSS and wF was observed with N-100m. The addition of N-200m significantly reduced FE by 23%, 33%, and 44% compared to those of WF-CS, WF-RH, and N-100m, respectively.