PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 2, Number 1, 2016
of hemicellulose-lignin due to the high degree of polymerisation of the natural cellulose (Rowell 2012, Pelaez-Samaniego et al. 2013). There are large quantities of this waste product that are still left unused or burnt. Bagasse usually contains residual sugars from cane production. These sugars may not be chemically compatible with resin binders and may interfere with bonding. Thus, to produce good quality board, the pith/core and residual sugars must be removed (Mobarak et al. 1982; Widyorini et al. 2005b). van Dam et al. (2004a,b) conducted an experiment using coconut husk to make high- density binderless boards. The binderless boards produced showed comparable mechanical properties to commercial boards, which opens commercial possibilities for the development of cheap building materials. The composition of husk material was dependent on the maturity of the nuts. Panyakaew and Fotios (2011) used a hot press method to make low-density binderless boards from coconut husks and bagasse. Both binderless boards produced met all standard board requirements (JIS - A 5908 2003), except for thickness swelling, as the bagasse binderless board provided superior properties compared to coconut husks. The boards produced were suitable for use as insulation materials. Other Materials Approximately 88.8% of the total biomass from bananas is discarded. This biomass, which comes from various parts of the banana, such as the bunch, pseudo-stem, and leaves, is classified as high content fibrous materials (Zuluaga et al. 2007). Quintana et al. (2009) produced binderless boards by performing pre-treatment on banana bunches via optimum condition values of 3.55 for severity, 200°C for pressing temperature, and 1.4MPa for pressing pressure, respectively. Severity values are related to high pressure and longer time practice during pre-treatment process that change nature of fibres used. Bamboo has high cellulose and lignin contents, as well as a short maturation period. It is easy to grow in forests or plantations. There are many types of bamboo, and it is sufficiently cheap to meet the extensive need for making boards. Bahari et al. (2008) managed to produce binderless bamboo fibreboards through the digesting process. The bending strength of binderless board exhibited a positive correlation with density and lignin content. Strength increased with bamboo age because of an increase in lignin. Charoenvai (2013) produced new insulating binderless particleboards from durian peels as a green alternative material for insulating products. He replaced formaldehyde based resin as an adhesive in binderless board with durian peel powder. These binderless boards possessed the best physical properties while yielding the lowest thermal conductivity. Meanwhile, Saadaoui et al. (2013) developed a binderless board using four diverse date palm lignocellulosic by-products via a hot-pressing process. Fibrillum, as one of the oil palm parts, has become a promising fibrous by-product, with high internal bond strength and low water absorption, as fibrillum has a high lignin content and good mechanical resistance. Lu et al. (2011; 2012) utilised wheat straw and rice straw with steam-explosion and liquid hot-water pre-treatments, respectively, to evaluate the influence of pre-treatment on the properties of panels. The results showed that pre-treatment using both methods was amongst the best ways to increase the degradation of chemical components, leading to excellent properties. The effects of pre-treatment are discussed in the next section. Angles et al. (1999) stated that pre-treated material leads to better strength and a smooth appearance. They produced binderless composites from pre-treated residual softwood via hydrolytic pre-treatment at a density of 1.0g/cm 3 . Angles et al. (2001) expanded their study
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Article 4 – Wood Panels
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