Suitability of Some Tropical Hardwoods for Cement-Bonded Wood-Wool Board Manufacture

Abstract

Keywords Solubitity of wood pH of wood pH of extractives Cement setting Wood-wool board Tropical hardwoods Schlüsselwörter (Sachgebiete) Löslichkeit von Holz pH-Wert von Holz pH-Wert von Holzextraktstoffen Zement-Bindung Holzwolleplatten Tropische Laubhölzer Suitability ofSome Tropical Hardwoods for Cement-Bonded Wood-Wool Board Manufacture SummarySolubility of 13 tropical hardwoods in cold water, hol water and 0.5 percent NaOH solution was determined and compared with one softwood species (Pinus kesiya) in this study, The pH of thc extract was also determined. The quantity and nature of extractives are discussed in rclation to their inhibitory effect in ccment setting, It is found that extraction with cold water is sufficicnt to remove the inhibitory extractives from most of the species tcstcd. Among the species tested Macranga peltata was found to be the most promising for cement-bonded wood-wool board manufacture and Terminalia paniculata, the most unsuitable, This study has shown that a knowledge of the pH of the cold water t hot water and mild alkali extract and the extent of acidity will help in not only screening the suitable species for cement-bonded wood-wool board manufacture but also in choosing the suitable method of extraction. Ober die Eignung einiger tropischer Laubhölzerfür die Herstellung Zement-gebundener Holzwolleplatten ZusammenfassungVon 13 tropischen Laubhölzern wurden die Löslichkeiten in Kalt-und Heißwasser sowie in 0,5%iger Natronlauge bestimmt und mit derjenigen von Nadelholz (Pinus kesiya) verglichen. Weiter wurden die pH-Werte ermittelt. Außerdem werden Menge und Eigenart der Extraktstoffe im Hinblick auf ihren Inhibierungseffekt bei der Zement-Abbindung erörtert. Es wurde festgestellt, daß die Extraktion mit Kaltwasser genügt, um die Hemmstoffe aus den meisten untersuchten Holzarten herauszuholen. Von den untersuchten Holzarten erwies sich Macranga peltata als am besten geeignet für die Herstellung zement-gebundener Holzwolleplatten, während Terminalia paniculata am schlechtesten abschnitt. Auf Grund der Untersuchung zeigt sich, daß die Kenntnis des pH-Wertes des Kaltwasser-und Heißwas-serauszuges und des Auszuges mit schwacher Natronlauge sowie des Säuregrades nicht nur beim Herausfinden der geeigneten Holzarten hilfreich sein kann, sondern auch bei der Wahl der geeigneten Extraktionsmethode für die Herstellung zement-gebundener Holzwolleplatten.

Testing and Enhancing The Compatibility of Five Saudi Wood Species for Cement-Bonded Particleboard Industry

“…These results are conformed in this study by the higher watersoluble substances content of lebbeck and leucaena as compared to that of buttonwood and Scots pine (Table 2). These results are in agreement with the results reported by many investigators (Moslemi et al, 1983, Gnanaharan and Dhamodaran, 1985, Nasser, 1996, Mohamed, 2004and Al Mefarraj and Nasser, 2008. With exception to lebbeck and leucaena, cementbonded particleboard can be made from the wood species used after either cold or hot extraction.…”

“…Species with higher solubility (cold or hot water) and acidic extract i.e., lebbeck and Madras thorn, gave lower compatibility with cement than those species with lower solubility contents and higher pH values i.e., Scots pine and buttonwood. Gnanaharan and Dhamodaran (1985) reported that species with low acidic extract along with low cold water solubility will be suitable for woodcement-wool board manufacture. These results are in agreement with the results of Jai and Chen (1977), Zhengatian and and Mohamed (2004).…”

“…In wood industries and to avoid hitch free production, wood-cement particleboards are generally made from wood species which have been tested and proved suitable (Ajayi and Badejo, 2005). So that wood species from different countries have been screened, tested and classified according to their suitability for CBP production using varying methods and techniques (Hofstrand et al, 1984, Gnanaharan and Dhamodaran, 1985, Yasin and Qurashi, 1990, Semple et al, 2002and Al-Mefarrej and Nasser, 2008.…”

Effects of pre-treatment of Curauá fibers on compatibility with portland cements

“…Some treatments performed on the lignocellulosic fibers prior to the production of the compounds show significant improvements in the inhibitory properties, among them the extraction with cold water [24], with hot [25] aqueous solution of sodium hydroxide (NaOH) 1% [15].…”

Adsorption of Cations from a Cement Suspension onto Lignocellulosic Substrates and its Influence on Cement Setting

“…[10] Simple removal of the extractives has worked in several cases to render woods more compatible with composite formation. Extraction with just cold water has been enough for several tropical hardwoods, [11] but some other wood species may require a harsh extraction, for example, with 1% NaOH. [12] Western larch (Larix occidentalis Nutt.…”