Impregnation of Bamboo (Gigantochloa Scortechinii) with Phenolic Resin for the Production of Dimensionally Stable Plybamboo

Low molecular weight phenol formaldehyde (LMwPF) resin was used to enhance the dimensional stability of bamboo strips (Gigantochloa scortechinii). Resin was impregnated into bamboo strips via vacuum process before the strips were converted into plybamboo. The present study was undertaken to develop a process to produce high dimensionally stable plybamboo. The work included evaluation of resin impregnation process, establishment of suitable drying/curing technique and final pressing of phenolic-treated bamboo strips. Evaluation of bonding properties, dimensional stability and mechanical properties of phenolic-treated plybamboo were also conducted. The bamboo strips were taken from basal and middle portions of bamboo culm. To treat the bamboo strips with LMwPF resin, firstly, a vacuum period of 1 hour was applied before the strips were soaked in resin for at least 90 minutes. The samples were later dried in an oven at 60°C for 9 hours. The mean weight percent gain (WPG) and moisture content (MC) of dried phenolic-treated bamboo strips were 14.5% and 7%, respectively. Drying the phenolic-treated bamboo strips for > 9 hours resulted in cupping of the strips. Phenolic-treated strips were then hot pressed for 5, 8, 11, 14 and 17 minutes at 14 kgm-2 and 140°C. Water absorption (WA), thickness swelling (TS) and linear expansion (LE) of the strips decreased when the curing time was extended from 5 minutes to 17 minutes but antishrink efficiency (ASE) increased. The mean value of modulus of rupture (MOR) for untreated strips (177 Nmm-2) was significantly lower than the phenolic-treated strips (224 Nmm-2) after 17 minutes pressing time. However, no significant difference was observed in modulus of elasticity (MOE) and compression parallel to grain. Results showed that the optimum pressing time for phenolic-treated strips was 11 minutes. This work also established an optimum pressing time to produce high dimensionally stable plybamboo. For this, phenolic-treated bamboo strips were glued together edge-to-edge using phenol resorcinol formaldehyde (PRF) resin to produce a veneer. The veneers were then assembled perpendicular to each other to form a 3-ply (12 mm) and 5-ply (20 mm) plybamboo using phenol formaldehyde resin as a binder. The plybamboos were hot pressed at an optimum pressing condition of 140oC (pressure 14 kgm-2) for 22 (3-ply) and 33 (5-ply) minutes. The bonding strength of the plybamboo obtained in this study met the minimum requirement of MS 228-1991. WA, TS, and LE of phenolictreated plybamboo were significantly lower compared to those of untreated plybamboo. The MOR, MOE and compression parallel to grain of the phenolic-treated plybamboo were significantly higher compared to those of untreated plybamboo. For 3-ply, the values were 164 and 127 Nmm-2 for MOR, and 19767 and 16778 Nmm-2 for MOE, and 60 and 41 Nmm-2 for compression parallel to grain, respectively. Similarly, for 5-ply phenolic-treated plybamboo the MOR, MOE and compression parallel to grain of were 38%, 30% and 33% respectively higher than those of untreated plybamboo. Generally, the treatment of bamboo strips with LMwPF resins were found to significantly improve the properties of plybamboo made from them

Properties and Utilisation of Tropical Bamboo (Gigantochloa Scortechinii), for Structural Plywood

The objectives of these study were to determine the physical and mechanical properties of 4-year-old Gigantochloa scortechinii culms and to evaluate the properties of plywood manufactured from the bamboo culms. Bamboo culms were split using hand splitter to produce splits. Strips were prepared by removing the epidermis and the inner skin using knife, whereas outer splits were prepared by removing the inner skin of the culm. For the bamboo plywood production, the bamboo strips were glued edge-to-edge using polyvinyl acetate resin into a 410 mm x 410 mm x 4 mm sized laminate. The laminates were then bonded perpendicularly to each other using phenol formaldehyde resin to produce tbreeply bamboo plywood. The assembly time was set at 30 min and bamboo plywood was consolidated by hot pressing at 140°C and pressure of 14 kg'cm2 for 6.5 minutes. Commercial structural plywood (Grade A) Merawan species with the same thickness as the bamboo plywood (12 mm) was used for comparison purposes. The results of the physical studies indicate that within the culm wall, the moisture content decreased from the interior towards the peripheral layer of the culm while the specific gravity increased. The moisture content decreased with height, whilst specific gravity increased. In the strip form, bamboo shrank: more in both radial and tangential directions than in the longitudinal direction. Between radial and tangential, shrinkage occurs more in radial than in tangential. The mean value of modulus of rupture (MOR) for the bamboo strips (179.6 N/mm2) showed no significant difference with splits (periphery layer oriented upward, 158.3 N/mm2) but a significant difference was observed when compared with the periphery layer oriented downwards (134.2 N/mm2)

Evaluation of wetting, structural and thermal properties of electrospun nanofibers at different pineapple leaf fiber / polyethylene terephthalate ratios

In this study, pineapple leaf fiber and polyethylene terephthalate electrospun nanofibers were produced via electrospinning process. Six ratios of pineapple leaf fiber/polyethylene terephthalate, namely 1/10; 1/7,5; 1/5; 1/1 and 1,3/1 were prepared and their wetting, structural and thermal properties were characterised. Wetting properties of this sample were studied using contact angle measurement. X-Ray Diffraction, differential scanning calorimetry and thermogravimetric analysis  were conducted to get better understanding on the structural and its thermal properties respectively. The results revealed that increasing the pineapple leaf fiber content simultaneously increased the ability of nanofibers to adsorb water as shown by lower contact angle degree with 81,6° and adsorption time of 15 seconds. An increase in pineapple leaf fiber ratio did not change the peak position in X-Ray Diffraction and no new peaks observed for any sample. However, the peak at 23° for samples with ratio 1/1 and ratio 1,3/1 exhibited higher intensity compared to that of pure polyethylene terephthalate. Thermal properties obtained from thermogravimetric analysis results suggested that thermal properties were not influenced by the pineapple leaf fiber ratio. Overall, pineapple leaf fiber/polyethylene terephthalate electrospun nanofibers produced at the ratio of 1/1 displayed the optimum performance

Adhesion and bonding characteristics of preservative-treated bamboo (Gigantochloa scortechinii) laminates.

This study were investigate the adhesion and bonding characteristics of bamboo (Gigantochloa scortechinii) strips and laminates treated with permethrin-based preservative (Light Organic Solvent-Based (LOSP) and Water-Based (WBP)) formulations, Tributyl Tin Oxide (TBTO) and borax. The bomboo culm were cut into strips and treated with those selected chemicals. The bamboo strips were then glued edge to edge to form a bamboo veneers before fabrication of the three ply perpendicular bamboo laminates. In this research the properties studied include wettability, buffering capacity, shear strength and wood failure. Untreated strips and bamboo strips which were boiled in water (100°C) were also tested for comparison purposes. Those strips treated with LOSP had higher contact angle (3°-9°) which reflects that the surface of the treated strips is less readily wetted. Whereas, borax-treated strips had the highest wetting rate where the value is 1°. In buffering capacity study shows that treated bamboo was more stable towards alkali. This is suggested that a buffering agent (Calcium carbonate) is required in the adhesive formulation to ensure sufficient curing of the resin. Preservative treatments on bamboo strips significantly affect shear strength and wood failure of the laminates. Shear and wood failure of the laminated bamboo were significantly reduced especially in the wet condition where, the range is 0 N mm-2 (WBP treated) to 0.65 N mm-2 (boiled-treated) when compared to untreated bamboo laminates (0.79 N mm-2). While, in dry condition test, the glue bond strength of were range from 0.64 N mm-2 (WBP-treated) to 2.04 N mm-2 (borax-treated). All chemicals and non-chemical treatment generally affects the glue strength of the bamboo laminates especially in wet condition test. In dry condition test there are slightly reductions in glue bond strength but the quality still meets the requirement in the British Standard Part 8: Specification for Bond Performance of Veneer Plywood

Impregnation and drying process of bamboo strips treated with low molecular weight phenol formaldehyde (LMwPF) resin

Impregnation and drying process of phenolic treated bamboo strips with low molecular weight phenol formaldehyde (LMwPF) resin. A study was under taken to determine an impregnation process and suitable drying duration for phenolic treated bamboo strip at basal and middle portions of Gigantochloa scortechinii. The strips were impregnated using vacuum process. After treated with low molecular weight phenol formaldehyde resin (LMwPF) using different duration of soaking, the weight percent gain (WPG) of bamboo strips was measured. The weight percent gain (WPG) of the impregnated G. scortechinii (basal and middle portions) increases when longer soaking time. After 150 minutes of soaking, the WPG were 14% and 15% for basal and middle portions, respectively. The specimens were then dried in an oven for 3 to 12 hours at 60°C. The reduction of moisture content (Mc) was plotted in a graph and analyzed. The suitable drying duration for bamboo strips were found to be between 6 to 9 hours. A significant difference (p<0.05) WPG was observed at middle portion but not within the basal portion. Moisture content of bamboo strips reduced with drying duration from average of 20% to 5%. However, the optimum drying duration should not exceed 9 hours after which the samples start to cupping

Enhancing the Properties of Mahang (Macaranga spp.) Wood through Acrylic Treatment in Combination with Crosslinker

Macaranga spp. (mahang) was treated with methyl methacrylate (MMA) in combination with a crosslinker trimethylolpropane trimethacrylate (TMPTMA). Polymerisation was carried out by catalyst heat treatment. A fairly consistent acrylic retention was found in the wood when treated with or without crosslinker. Polymerisation of MMA is at maximum with 1% crosslinker and beyond this concentration the polymerisation decreased. The dimensional stability in terms of anti-swelling efficiency (ASE) was determined and found to be improved on treatment. Water absorption was also found to be decreased considerably for treated wood. Mechanical strength of the treated wood in terms of modulus of rupture (MOR), compressive stress and hardness were improved, but the stiffness (modulus of elasticity) did not change. In terms of specific strength (strength to density ratio), the treated material is less stiffer and less strength in lateral direction compared to untreated wood. However, the specific compressive strength perpendicular to the grain and hardness of the treated material were superior compared with the untreated

Properties of medium-density fibreboard (MDF) made from treated empty fruit bunch of oil palm

The objective of this study was to evaluate the physical and mechanical properties of experimental medium density fibreboard (MDF) panels manufactured from empty fruit bunch (EFB) of oil palm (Elaeis guineensis). Panels were made from EFB treated with boiling water, soaked in sodium hydroxide (NaOH) or their combination by using phenol formaldehyde at 8, 10 and 12% based on oven-dry weight of fibre. Mechanical and physical properties including modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength, thickness swelling and water absorption of the samples were determined according to the Malaysian Standards (MS 1787: 2005). Based on results of this work, it seems that EFB can be used as raw material to manufacture value-added MDF with accepteble properties based on the standards. Panels made from fibres treated with NaOH in 12% resin produced the highest MOR (31.4 MPa). Fibres treated with the combination of NaOH and boiling water resulted in panels with reduced bending properties. All types of treatments enhanced dimensional stability of panels. All treated EFB fibres were less sensitive when exposed to alkaline condition compared with acidic condition

Mechanical properties of 10-year-old sentang (Azadirachta excelsa) grown from vegetative propagation

Mechanical properties of 10-year-old sentang (Azadirachta excelsa) grown from vegetative propagation. This paper reports the mechanical properties of sentang (Azadirachta excelsa) wood cut from trees that were planted by vegetative propagation, their variations along tree height and also between sapwood and heartwood. The correlation between selected anatomical properties as well as density and mechanical properties were also presented. There was no significant difference in modulus of rupture between wood from seedling and rooted- cutting trees. However, wood from rooted-cutting trees showed higher modulus of elasticity compared with wood from seedling trees. On the other hand, compression and shear parallel to the grain were significantly higher in wood planted from seedling compared with wood from rooted-cutting trees. There was an increase in mechanical properties at the bottom portion towards the top irrespective of the planting technique. Mechanical properties were higher in heartwood than in sapwood. Mechanical properties were correlated with anatomical properties rather than density. Rooted cutting could be a promising method for planting sentang, apart from seedling

Equilibrium moisture content and volumetric changes of Gigantochloa scortechinii

Equilibrium moisture content and volumetric changes of Gigantochloa scortechinii. Relative humidity (RH) is known to affect the moisture content (MC) of bamboo but to date, only the maximum shrinkages at the tangential and radial directions were commonly determined. For bamboo to be glue-laminated and used as building components, the hygroscopicity of bamboo split and strip, and its effects on the shrinkage/swelling behaviour in relative humidities between 12 and 93% were studied. The equilibrium moisture content (EMC) and dimensional changes of Gigantochloa scortechinii (buluh semantan) were determined with the fibre saturation point (FSP) obtained by extrapolation. Experimental EMC values obtained at various levels of RH showed little variation between bamboo split and strip. However the degree of volumetric shrinkage and swelling changes varied between the variables studied. In transverse section, the bamboo strip is relatively stable in shrinkage at lower relative humidity, although during adsorption the volumetric swelling is high. The mean FSP for G. scortechinii was 24.28%. This study showed that the readiness of bamboo to dimensional changes below FSP was of prime concern. By understanding the hygroscopic characteristics and behaviour of G. scortechinii, users would be able to understand the limitations of the material and find alternatives to prevent these changes before it could be used as building components