Evaluation of the Properties of 4-Year Old Rubberwood Clones Rrim 2000 Series for Particleboard Manufacture

With drastic depleting rubberwood supply, the Lembaga Getah Malaysia (LGM) has identified new clones of rubber trees that are expected to produce not solely latex but also timber. Among these clones, several clones from RRIM 2000 series were found to be fast growing with high yield of latex, high growth vigor, good growth form and are very suitable for timber production, particularly for the biocomposite industries. In this study, particleboards were manufactured from rubber tree clones of RRIM 2002, RRIM 2020 and RRIM 2025 which are also categorized as Latex Timber Clone (LTC). The properties of these particleboards were compared with those made from the currently planted tree clone ; PB 260. All clones from RRIM 2000 series were planted at 1000-1100 trees planting density and harvested for this study at 4 year-old. The resin used was E1-grade urea formaldehyde (UF) and the target density of the particleboard was 700 kgm-3. The basic and adhesion properties of these woods were evaluated and discussed in relation to the board performance i.e. physical and mechanical properties, and dimensional stability. These properties were determined according to Japanese Industrial Standard for Particleboard (JIS A 5908-2003). Among the clones studied, RRIM 2002 showed the best overall wood basic properties and board performance, which are comparable to or better than those of matured clone PB 260. The 25-year old PB 260 gives the highest specific gravity (0.601), lowest moisture content (70%), longer fibre length (1.3 mm) and thickest fibre wall thickness (6.2 μm). Clone RRIM 2002 gives comparable wood basic properties except for specific gravity (0.570), higher wood moisture content (94%) relatively longer fibre length (1.4 mm) and thicker fibre wall (5.5 μm). Except for specific gravity, the other two clones give poorer overall wood properties particularly the RRIM 2025. Both clones, however, produced relatively high specific gravity, 0.589 and 0.582 for RRIM 2020 and RRIM 2025. The adhesion properties of all 4-year old clones show almost similar properties. For the particle analysis, PB 260 gives the highest acceptable particle distribution (63.5%), whilst RRIM 2002, RRIM 2020 and RRIM 2025 had respectively, 56.8%, 57.9%, 58.3%. The particleboards of PB 260, RRIM 2002, RRIM 2020 recorded similar modulus of elasticity (MOE) of 2156 Nmm-2, 2145 Nmm-2, and 2122 Nmm-2, respectively, which were significantly higher (p< 0.05) than that of RRIM 2025 board (1931 Nmm-2). The board’s strength (MOR) of clones RRIM 2002, RRIM 2020, RRIM 2025 and PB 260 were 20.4 Nmm-2, 19.9 Nmm-2, 18.0 Nmm-2 and 21.0 Nmm-2, respectively. The internal bond (IB) of all of the boards ranged from 1.24 Nmm-2 to 1.49 Nmm-2, and were not significantly different. Among the four rubber tree clones, PB 260 board was the most stable as indicated by the low values in thickness swelling (RRIM 2002, 22.4 %; RRIM 2020, 21.2 %; RRIM 2025, 19.7 % and PB260, 18.1 %). No significant difference in water absorption of particleboard was found for all clones studied. The overall results indicate that 4-year old rubberwood clones can be used as raw material for particleboard manufacture where clone RRIM 2002 as the most suitable clone as it produced comparable particleboard properties with matured clone particleboard

Retting process of some bast plant fibres and its effect on fibre quality : a review.

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

Effects of polymorph transformation via mercerisation on microcrystalline cellulose fibres and isolation of nanocrystalline cellulose fibres

Cellulose I can be irreversible transformed into cellulose II via mercerisation or regeneration treatments. In the past few decades, mercerisation was used mainly to improve fibre properties for textile industries. A few studies have focused on the effects of mercerisation treatment on the cellulose polymorph itself and after it was downscaled to nanosize. This study aims to characterise the micro size crystalline cellulose after complete polymorph conversion via mercerisation technique and investigate its effects on isolation to nanosize crystalline cellulose. A microcrystalline cellulose (MCC) was purchased and converted into cellulose II via mercerisation technique. Sulphuric acid hydrolysis was carried-out to produce nanocrystalline cellulose (NCC). The MCC and NCC of different polymorphs were then characterised and analysed for its crystallography, morphology, particles size distribution and thermal stability using wide-angle X-ray diffraction (WXRD), electron microscopes, dynamic light scattering analyser and thermogravimetric analyser, respectively. Both MCC and NCC fibres showed complete conversion of cellulose I to cellulose II and decrement of crystallinity index (CI). Electron micrographs revealed that both cellulose II polymorph fibres (MCC II and NCC II) were morphological affected. The analysis of size distribution and dimension measurement confirmed that mercerisation treatment causing increment in fibre diameter and shortened length. The thermal stability of both cellulose II polymorph fibres (MCC II and NCC II) was also found to be improved

Physicochemical characterization of pulp and nanofibers from kenaf stem

The aim of this study was to isolate cellulose nanofibers from kenaf (Hibiscus cannabinus) stem using chemo-mechanical treatments. The fiber purification method included pulping and bleaching processes whereas the mechanical treatments employed to isolate kenaf nanofibers were grinding and high pressure homogenizing. Kenaf nanofibers were found to have diameters in the range of 15-80 nm while most nanofibers have diameters within the range 15-25 nm. Fourier transform infrared spectroscopy (FTIR) showed that the chemical treatments removed lignin and most of the hemicelluloses from the fibers. The thermal characteristics of the fibers were analyzed using the technique of thermogravimetric analysis (TGA) which demonstrated that these characteristics were enhanced noticeably both for the bleached pulp and nanofibers. On the other hand, the X-ray analysis indicated that both chemical and mechanical treatments can improve the crystallinity of fibers

Ternary nanocomposite system composing of graphene nanoplatelet, cellulose nanofiber and jatropha oil based waterborne polyurethane: characterizations, mechanical, thermal properties and conductivity

This work aims to evaluate the performance of graphene nanoplatelet (GNP) as conductive filler with the presence of 0.5 wt.% cellulose nanofiber (CNF) on the physical, mechanical, conductivity and thermal properties of jatropha oil based waterborne polyurethane. Polyurethane was made from crude jatropha oil using an epoxidation and ring-opening process. 0.5, 1.0, 1.5, 2.0 wt.% GNP and 0.5 wt.% CNF were incorporated using casting method to enhance film performance. Mechanical properties were studied following standard method as stated in ASTM D638-03 Type V. Thermal stability of the nanocomposite system was studied using thermal gravimetric analysis (TGA). Filler interaction and chemical crosslinking was monitored using Fourier-transform infrared spectroscopy (FTIR) and film morphology were observed with field emission scanning electron microscopy (FESEM). Water uptake analysis, water contact angle and conductivity tests are also carried out. The results showed that when the GNP was incorporated at fixed CNF content, it was found to enhance the nanocomposite film, its mechanical, thermal and water behavior properties as supported by morphology and water uptake. Nanocomposite film with 0.5 wt.% GNP shows the highest improvement in term of tensile strength, Young’s modulus, thermal degradation and water behavior. As the GNP loading increases, water uptake of the nanocomposite film was found relatively small (<1%). Contact angle test also indicates that the film is hydrophobic with addition of GNP. The conductivity properties of the nanocomposite film were not enhanced due to electrostatic repulsion force between GNP sheet and hard segment of WBPU. Overall, with addition of GNP, mechanical and thermal properties was greatly enhanced. However, conductivity value was not enhanced as expected due to electrostatic repulsion force. Therefore, ternary nanocomposite system is a suitable candidate for coating application

Effect of cellulose nanofibrils on the properties of Jatropha oil-based waterborne polyurethane nanocomposite film

The objective of this work was to study the influence of cellulose nanofibrils (CNF) on the physical, mechanical, and thermal properties of Jatropha oil-based waterborne polyurethane (WBPU) nanocomposite films. The polyol to produce polyurethane was synthesized from crude Jatropha oil through epoxidation and ring-opening method. The chain extender, 1,6-hexanediol, was used to improve film elasticity by 0.1, 0.25, and 0.5 wt.% of CNF loading was incorporated to enhance film performance. Mechanical performance was studied using a universal test machine as specified in ASTM D638-03 Type V and was achieved by 0.18 MPa at 0.5 wt.% of CNF. Thermal gravimetric analysis (TGA) was performed to measure the temperature of degradation and the chemical crosslinking and film morphology were studied using Fourier-transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The results showed that when the CNF was incorporated, it was found to enhance the nanocomposite film, in particular its mechanical and thermal properties supported by morphology. Nanocomposite film with 0.5 wt.% of CNF showed the highest improvement in terms of tensile strength, Young’s modulus, and thermal degradation. Although the contact angle decreases as the CNF content increases, the effect on the water absorption of the film was found to be relatively small (<3.5%). The difference between the neat WPBU and the highest CNF loading film was not more than 1%, even after 5 days of being immersed in water

Green nanocomposites from cellulose nanowhiskers and Jatropha oil-based polyurethane

A green nanocomposite film from cellulose nanowhiskers (CNWs) and Jatropha oil-based polyurethane (JOPU) was prepared. A commercial grade of microcrystalline cellulose derived from wood pulp was purchased and isolated to CNW via acid hydrolysis using 65% (w/w) sulfuric acid. JOPU was produced using in-house synthesis of Jatropha-oil polyol and 4,4′-diphenyl-methane diisocyanate (MDI). Dimethylformamide (DMF) was used as a polar organic solvent to disperse CNWs incorporated with JOPU at different ratios. Green nanocomposite films were prepared by casting in Teflon petri dish and thermal curing of the stable suspensions under vacuum conditions. Both CNW and composite films were characterized. The morphology of CNW was examined by using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Chemical structures of JOPU and JOPU/CNW films were analyzed using Fourier transform infrared spectroscopy (FTIR). Thermal stability tests of the films were carried out using thermogravimetric analysis (TGA). Mechanical properties, such as tensile strength, Young modulus, and elongation at break, were investigated. Other properties such as density and water uptake were also determined. It can be concluded that composite films made from JOPU with CNW as filler showed an improved performance over JOPU films

Effect of fibre length and sea water treatment on mechanical properties of sugar palm fibre reinforced unsaturated polyester composites

This study presented the effect of different fibre length and seawater treatment on mechanical properties of the fabricated composites. The composite was reinforced with fixed 30wt.% of fibre loading. Sugar palm was treated using sea water for 30 days and have been cut into three different lengths by 5cm, 10cm and 15cm. The mechanical properties of the untreated and treated fibre with different fibre length composites were characterised includes tensile test and flexural test. Treated sugar palm fibre composites with 15cm fibre length exhibited higher tensile strength at 18.33 MPa. However, it shows the lowest value for the tensile modulus at 4251.96MPa. The flexural strength shows an increasing trend as the fibre length increased up to 15cm and the maximum flexural strength was exhibited by treated sugar palm fibre with 5 cm at 80.80MPa

Degradation of medium density fibreboard and particleboard mechanical performance after exposed to different environmental condition

Wood or natural-based products will continue to be susceptible to degradation. However, this degradation process can be slow-down by introducing additives or certain treatment. The properties (i.e. mechanical, physical, bonding etc.) of wood-based panel such as Medium Density Fiberboard (MDF) and Particleboard (PB) degrades in function with period of usage or exposure due to factors in surrounding conditions. This work focuses on the study of mechanical performance deterioration for MDF and PB after condition in the air-conditioned room and ambient for three months. Through this study, comparisons of various board variables (board types, exposure conditions, board thicknesses, resin types) influences the board performance degradation process. The project also studied the effects of cold-water immersion (12, 24 and 72 hours) to the mechanical properties of the board. The mechanical performance of boards was evaluated based on static bending (Modulus of Elasticity and Modulus of Rupture) and internal bonding tests after exposed for 3 months. All boards (MDF and PB) used in this study were obtained from local commercial panel manufacturer and test according to JIS A 5908-1994. The findings show that all the variables studied: exposure conditions, resin type, board thickness and board type respectively, have a significant effect on the diminished strength of panel strengths. The conditioning method and board type found to influence foremost compared with resin type. Exposing both of panels in air-conditioned room found to delay the degradation compared with ambient exposure for tested properties; MOE, MOR and IB respectively. The board thickness seems influenced the degradation of the board in any exposure conditions; air conditioned, ambient or cold-water soaking. The thicker of the board, the greater the degradation occurred

Chemical and Thermo-Mechanical Properties of Waterborne Polyurethane Dispersion Derived from Jatropha Oil

Nowadays, there is a significant trend away from solvent-based polyurethane systems towards waterborne polyurethane dispersions due to government regulations requiring manufacturers to lower total volatile organic compounds, as well as consumer preference for more environmentally friendly products. In this work, a renewable vegetable oil-based polyol derived from jatropha oil was polymerized with isophorone diisocyanate and dimethylol propionic acid to produce anionic waterborne polyurethane dispersion. Free standing films with up to 62 wt.% bio-based content were successfully produced after evaporation of water from the jatropha oil-based waterborne polyurethane (JPU) dispersion, which indicated good film formation. The chemical and thermomechanical properties of the JPU films were characterized. By increasing the OH numbers of polyol from 161 mgKOH/g to 217 mgKOH/g, the crosslinking density of the JPU was significantly increased, which lead to a better storage modulus and improved hydrophobicity. Overall, JPU produced from polyol having OH number of 217 mgKOH/g appears to be a promising product for application as a binder for wood and decorative coatings