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Md. Tahir P.,Institute of Tropical Forestry and Forest Products | Ahmed A.B.,Institute of Tropical Forestry and Forest Products | SaifulAzry S.O.A.,Institute of Tropical Forestry and Forest Products
BioResources | Year: 2011

Retting is the main challenge faced during the processing of bast plants for the production of long fibre. The traditional methods for separating the long bast fibres are by dew and water retting. Both methods require 14 to 28 days to degrade the pectic materials, hemicellulose, and lignin. Even though the fibres produced from water retting can be of high quality, the long duration and polluted water have made this method less attractive. A number of other alternative methods such as mechanical decortication, chemical, heat, and enzymatic treatments have been reported for this purpose with mixed findings. This paper reviews different types of retting processes used for bast plants such as hemp, jute, flax, and kenaf, with an emphasis on kenaf. Amongst the bast fibre crops, kenaf apparently has some advantages such as lower cost of production, higher fibre yields, and greater flexibility as an agricultural resource, over the other bast fibres. The fibres produced from kenaf using chemical retting processes are much cleaner but low in tensile strength. Enzymatic retting has apparent advantages over other retting processes by having significantly shorter retting time and acceptable quality fibres, but it is quite expensive.

Malek F.H.A.,Institute of Tropical Forestry and Forest Products | Zainudin E.S.,Institute of Tropical Forestry and Forest Products | Zainudin E.S.,University Putra Malaysia | Zainudin E.S.,Brunel University | And 2 more authors.
Applied Mechanics and Materials | Year: 2014

Pultrusion manufacturing process is a well established technique for the cost-effective production of high-modulus and lightweight composite materials having constant cross-sectional profiles. A study was carried out to analyze the effect of additives on bending strength of pultruded hybrid reinforced resol type phenolic composite. Glassfibre roving and kenaf fibre hybrid were reinforced in resol type phenolic. A series of bending tests were performed by varying the loading percentage of two type's pultruded fibres,without additives and with additives. From the results, it was found that the modulus of strength of composites with additives display higher values as compared to composite without additives. The presence of additives were able to synergistically interact with both fibres and finally improve the interaction between them. Analysis of the fracture surface from the bending test were carried out using Dino-Lite digital microscope. © (2014) Trans Tech Publications, Switzerland.

Rahnama N.,University Putra Malaysia | Mamat S.,University Putra Malaysia | Shah U.K.M.,University Putra Malaysia | Shah U.K.M.,Institute of Tropical Forestry and Forest Products | And 3 more authors.
BioResources | Year: 2013

Use of alkali-pretreated rice straw and untreated rice straw as substrates for enzyme production under solid-state cultivation was investigated. Cellulase produced from untreated rice straw showed higher activity of FPase, CMCase, β-glucosidase, and xylanase at 6.25 U/g substrate, 111.31 U/g substrate, 173.71 U/g substrate, and 433.75 U/g substrate respectively, as compared to 1.72 U/g substrate, 23.01 U/g substrate, 2.18 U/g substrate, and 45.46 U/g substrate for FPase, CMCase, β-glucosidase, and xylanase, respectively, when alkali-pretreated substrate was used. The results of the X-ray diffractogram analysis showed an increase in relative crystallinity of cellulose in alkali-pretreated rice straw (62.41%) compared to 50.81% in untreated rice straw. However, the crystalline structure of cellulose was partially disrupted after alkali pretreatment, resulting in a decrease in absolute crystallinity of cellulose. The higher the crystallinity of cellulose, the more cellulase production was induced. The structural changes of rice straw before and after alkali pretreatment were compared by using Scanning Electron Microscopy. Fungal mycelial growth was also observed for both untreated and alkali-pretreated substrates. The results of this study indicated that untreated rice straw is a better substrate for cellulase and xylanase production under solid-state fermentation with low environmental impact.

Abdul-Hamid H.,Institute of Tropical Forestry and Forest Products | Abdul-Hamid H.,University Putra Malaysia | Abdu A.,University Putra Malaysia | Ismail M.-K.,University Putra Malaysia | And 2 more authors.
Asian Journal of Plant Sciences | Year: 2011

Gas exchange is important for determining the species plasticity. However, study on gas exchange in dipterocarp is almost non-existence and this study may provide useful information for future references. The study was conducted at the Compartment 14, Ayer Hitam Forest Reserve, Puchong and Selangor, Malaysia. The main objective of this study was to determine the leaf gas exchange of three dipterocarps, Shorea platyclados V. SI. ex Foxw. (meranti bukit), Shorea assamica Dyer forma globifera (Ridl) Sym. (meranti pipit) and Anisoptera marginata Korth. (mersawa paya) planted in different sizes of gap. The results showed that the gas exchange parameters were not significantly different between species except stomatal conductance (Gs) and transpiration rate (E L). Insignificant differences of all the gas exchange parameters were also observed between planting designs. Meanwhile, the correlation analysis showed that insignificant effect of design on species for net photosynthesis (A net) is due to the effect of internal CO 2 concentration (Ci). However, the significant difference observed for transpiration rate (EL) between species might be due to the significant roles of stomata conductance (Gs). Overall, the higher tropical species plasticity by introducing reciprocal planting in rehabilitation programme has produced mixed results. © 2011 Asian Network for Scientific Information.

Anokye R.,University Putra Malaysia | Anokye R.,Kumasi Polytechnic | Bakar E.S.,University Putra Malaysia | Bakar E.S.,Institute of Tropical Forestry and Forest Products | And 3 more authors.
Construction and Building Materials | Year: 2016

The objective of this work was to evaluate the mechanical properties of laminated bamboo timber (LBT) manufactured from bamboo (Gigantochloa scortechinii). Bamboo strips containing nodes were used to produce laminated samples. Each bamboo mat was arranged with 5 cm intervals ranging from 0 cm to 15 cm between the nodes in successive laminae. Phenol formaldehyde (PF) and polyvinyl acetate (PVAc) were used at two spread rates of 200 g/m2 and 250 g/m2. The best mechanical properties were found in samples without nodes. Increasing intervals also resulted in increasing strengths. In all the mechanical properties studied, PF had higher strength with 200 g/m2 spread rate except for shear where PVAc had similar values with PF. It appears that interval levels in the joints influenced the overall mechanical properties of the samples. © 2015 Elsevier Ltd. All rights reserved.

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