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.
This paper presents the mechanical properties, veneer recovery including the cost benefits, of 3-, 5-, and 7-yr-old falcata [Falcataria moluccana (Miq.) Barneby & J. W. Grimes] for veneer production. Mechanical properties covered modulus of rupture (MOR), stress at the proportional limit, and modulus of elasticity (MOE) in static bending; compression paralleland perpendicular-to-grain; shear; and hardness and toughness. The study was conducted to evaluate the effects of age on these properties and the cost-benefits of converting the species at different ages, and to recommend the optimum age and price for the utilization of the species for veneer production. The experimental materials consisted of six plus-size trees each per age from superior seeds of known origin in Caraga, Philippines. Standard procedures for testing the strength properties of timber (ASTM D143-14) were followed. Veneering was conducted using a spindleless lathe with a fixed setting for each designated veneer thickness output. Gross veneer recovery was 52% for both 3- and 5-yr-olds and 55% for the 7-yr-old. Net recovery, on the other hand, was 46% for the 3- and 5-yr-olds while 49% for the 7-yr-old. Utilizing falcata trees as young as 3-yr-old can generate positive cash flows for veneering plants, making it a worthwhile investment. However, from the perspective of falcata farmers and plantation owners, selling at 3-yr-old would be unfavorable considering the low selling price.
Two commercial bamboo species – namely, “kauayan tinik” (Bambusa blumeana J.A. and J.H. Schultes) and giant bamboo [Dendrocalamus asper (Schultes et.) Backer ex Heyne] – were treated by thermal modification (TM) or heat treatment in a steam environment using temperature and duration settings of 175 °C – 30 min and 200 °C – 30 min. The effect of TM and the presence and absence of node on the physical and mechanical properties of bamboo were studied. Physical [moisture content (MC), thickness swelling (TSw), water absorption (WA), and specific gravity] and mechanical (flexural, compression, and tensile strength) properties were determined. A factorial experiment in a completely randomized design (CRD) was used to analyze the data. Results showed that TM improved the dimensional stability of bamboo as evidenced by lower MC, TSw, and WA compared to control samples. Except for tensile strength, the flexural and compressive strength of heat-treated bamboo did not significantly change at 175 °C – 30 min compared to the control. The presence of nodes, on the other hand, significantly reduced the bamboo samples’ flexural and tensile strength. Generally, TM improved the dimensional stability of bamboo without significantly affecting the mechanical properties at 175 °C – 30 min. At 200 °C – 30 min, a slight reduction in strength was observed, especially for D. asper.
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