Preparation and Properties Enhancement of Oriented Strand Board Made from Tropical Fast Growing Tree Species

• Main Authors: Wahyu Hidayat, WahyuHidayat
• Other Authors: Prof. Hong-Ding Soong
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/02570600337014796660

碩士 === 國立嘉義大學 === 林產科學系研究所 === 97 === ABSTRACT This study evaluates the effects of strand pretreatment and strand combination on the properties of oriented strand board (OSB) made from tropical fast growing tree species. The raw materials of OSB panels were logs and they were flaked using a disc flaker. The resulting strands were analyzed to determine their dimension and curliness. It was observed that the average length, width, and thickness of the strands were 69 mm, 23 mm, and 0.73 mm, respectively. The average value of aspect ratio and slenderness ratio were 3 and 95. Prior to OSB manufacturing, strands were pretreated with cold water soaking at 20�aC for 24 h, hot water soaking at 90�aC for 2 h, and chromium copper boron (CCB) soaking with concentration of 2% for 6 h, respectively. Three layers OSB bonded with 7% of methylene diphenyl isocyanate (MDI) resin were produced with the core layer orientation perpendicular to the face and back layers. Nine strand combinations from Maesopsis eminii (M), Paraserianthes falcataria (S), and Acacia mangium (A) were manufactured, namely MMM, MSM, MAM, SSS, SMS, SAS, AAA, AMA, and ASA. The physical and mechanical properties of the boards were evaluated based on CNS 2215 (2006) as standard test methods for evaluating properties of particleboard and the results were further compared to CSA 0437.0 standard for grade O-1 OSB panels. The board properties tested included density, moisture content (MC), water absorption (WA), thickness swelling (TS), modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength (IB), and wood screw holding power (SHP). In addition, density profile and weight loss percentage (WLP) after subterranean termite attack were also determined. The results revealed that strand pretreatment showed significant effect on all board properties except MOE and MOR in perpendicular direction, and TS for 2 h. The results indicated that the WA of OSB made from cold water and hot water-pretreated strands were significantly improved while compared to untreated board. Strand pretreatments significantly improved durability of OSB against subterranean termites attack (Macrotermes gilvus) compared to untreated one. Strand combination showed significant effect on all board properties except MOR, SHP, and WLP. OSB manufactured from wood species with lower density (Paraserianthes falcataria) had low dimensional stability which indicated by the higher value of WA and TS. Mixing the wood species with strands from higher wood density (Maesopsis eminii and Acacia mangium) significantly improved dimensional stability of the board. Conversely, OSB manufactured from higher density had low MOE and MOR values due to low compression ratio, the values increased by mixing the wood species with strands from lower wood density. Almost all physical and mechanical properties of OSB made from fast growing tree species met the requirement of CSA 0437.0 standard for grade O-1 OSB panels. The values of TS for 24 h soaking for MSM board made from CCB-pretreated strands, SSS board and SMS board made from cold water-pretreated, hot water-pretreated and CCB-pretreated strands, SAS board made from cold water-pretreated and CCB-pretreated strands, and ASA board made from CCB-pretreated strands could not meet the standard requirement. Regarding mechanical properties, AMA board made from CCB-pretreated strands could not meet the standard requirement for MOR in parallel direction. The MOE values of MSM board made from CCB-pretreated strands, SSS board made from cold water-pretreated and CCB-pretreated strands, AAA board made from cold water-pretreated strands, and AMA board made from CCB-pretreated strands could not meet the standard requirement of MOE in parallel direction. The IB strength values of SSS board, SAS board, AMA board and ASA board made from CCB-pretreated strands also could not meet the standard requirement. The results of this study showed the feasibility of using wood strands of fast growing tree species from planted forests for OSB manufacturing, it is important to qualify appropriate raw material supply for the board industry.