PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 2, Number 1, 2016
Table 2. Chemical Composition and Moisture Content of Natural Fibres Kenaf Kenaf ( Hibiscus cannabinus L. ) is a fast-growing annual plant. The kenaf stem comprises two major parts of fibre, with a ratio of 30:70 of the fibrous outer-bast and the woody inner core; these differ greatly in fibre morphology and chemical composition (Voulgaridis et al. 2000). The kenaf core is lighter and more porous compared to the bast, with a density of 0.10 to 0.20g/cm 3 . It has the potential to become a sustainable lignocellulosic raw material. It is rich in hemicellulose content, although the lignin content of kenaf is low. A few studies (Okuda and Sato 2004, 2009; Widyorini et al. 2005; Xu et al. 2006) have been performed on kenaf to produce binderless boards using the heat and steam processes. Okuda and Sato (2004) manufactured binderless boards using kenaf core through a hot- press method to investigate the properties of the boards using various manufacturing conditions. Results showed that the optimum pressing pressure, temperature, and time were 5.3MPa, 180°C, and 10 min, respectively, with a board density of 1.0g/cm 3 . The boards’ properties exceeded minimum requirements (JIS – A 5908 2003). In another study (Okuda and Sato 2006), the researchers investigated the water resistance properties of binderless boards. They were able to produce binderless boards with higher water resistance compared to boards produced with synthetic resins. Also, Okuda et al. (2006a,b) examined the chemical changes in kenaf binderless board using various pressing temperatures and by adding extra materials such as acetic acid during board production. Chemical changes occurred, as some of the lignin and hemicelluloses decomposed during the hot press process. These extra materials, although optional, helped to accelerate chemical changes as well as improve board properties. Xu et al. (2004) produced low-density binderless boards using kenaf core for thermal and sound insulation purposes. The boards produced exhibited good mechanical properties and reached similar values of thermal conductivity as insulation materials. Although the boards showed good internal bond performance, they experienced high water absorption because of their porous characteristics. Xu et al. (2006) furthered the investigation by producing boards via a refining process, in which it was discovered that high steam pressure and long cooking time would lead to improved internal bond strength and lower
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Article 4 – Wood Panels
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