In the second paper in this series, we test the hypothesis that cement-setting accelerators with ... more In the second paper in this series, we test the hypothesis that cement-setting accelerators with the ability to chelate phenolic extractives will be more effective at improving the physical properties of wood-wool cement boards made from the heartwood of Acacia mangium than conventional accelerators. Furthermore, we assess whether the use of chelating accelerators will allow boards with acceptable properties to be manufactured from A. mangium wood-wool that has not been subjected to preliminary aqueous extraction to remove phenolic extractives. Batches of wood-wool from A. mangium containing approximately 75% heartwood were either soaked in water or used in their native form. The batches were then treated with an aqueous solution containing an inorganic compound (generally 0.05 or 0.1 M) selected for its ability to accelerate the hydration of Portland cement, and in the case of 5 of the 11 compounds tested, chelate phenolic extractives. Individual wood-wool cement boards were manufactured from each treated batch of wood-wool and tested for their dry and wet bending strength (MOR), stiffness (MOE), and water absorption properties. Boards made from untreated or water-soaked wood-wool acted as controls. The MOR and MOE of boards made from unsoaked A. mangium wood-wool and treated with the chelating accelerators tin or ferric chloride at 0.1 M concentration were 10.8 and 10.9 MPa and 2256 and 2178 MPa, respectively. These same boards showed less than 5% thickness swelling after 24-h immersion in water. In contrast most of the boards containing a conventional non-chelating accelerator had no structural integrity. The combination of a chelating accelerator and a conventional accelerator was particularly effective at improving the physical properties of boards made from unsoaked wood-wool. We conclude that wood-wool cement boards with acceptable physical properties can be manufactured from A. mangium heartwood by treating wood-wool with inorganic compounds that have the ability to chelate phenolic extractives and accelerate the hydration of Portland cement. Our findings could eliminate the need to pre-soak A. mangium wood-wool in water during the manufacture of wood-wool cement boards and may have broader relevance to the manufacture of wood-wool cement boards from other hardwood species containing phenolic extractives.
Retardancy and Mechanical Properties of Polylactic Acid with a Biodegradable Fire-Retardant Fille... more Retardancy and Mechanical Properties of Polylactic Acid with a Biodegradable Fire-Retardant Filler System Based on Bamboo Charcoal.
European Journal of Wood and Wood Products, May 3, 2015
This study is first in a series investigating the combination of Moso bamboo (Phyllostachys pubes... more This study is first in a series investigating the combination of Moso bamboo (Phyllostachys pubescens Mazel) and aspen (Populus tremuloides Michx.) to fabricate hybrid strand based panel composites. Here the wood and bamboo strands were evenly mixed together to form a thin, uni-directional strandboard 10 mm in thickness. The use of 30 % aspen strands was to improve the compaction and consolidation of the hard, uncompressible bamboo. The effects of replacing most of the aspen strands (70 %) with bamboo strands on board strength properties (IB, MOR, MOE) and moisture resistance were assessed. The effect of strands cut from the node free (internode) or node tissue portions of the culm on board properties was also systematically investigated. Substitution with 70 % internode Moso bamboo strands increased MOR by over 40 % compared with pure aspen and significantly lowered thickness swell and water absorption. Substituting aspen with the bamboo strands resulted in no change in MOE, in keeping with the tendency for natural Moso bamboo tissue to be high in bending strength and fracture toughness but lower in specific stiffness. The presence of node tissue in the bamboo strands significantly reduced the consolidation and mechanical properties of the composites.
... 1ANU Forestry, The Australian National University, ACT 0200, Australia. Email: Kate. Semple@ ... more ... 1ANU Forestry, The Australian National University, ACT 0200, Australia. Email: Kate. Semple@ anu. edu. ... 1989), result-ing in poor bonding in wood–cement composites. This is a major impediment to the use of A. mangium as a raw material for WWCB manu-facture. ...
Understanding maturation stress and wood properties of poplar tension wood are critical for impro... more Understanding maturation stress and wood properties of poplar tension wood are critical for improving lumber yields and utilization ratio. In this study, Released Longitudinal Maturation Strains (RLMS), anatomical features, physical and mechanical properties, and nano-mechanical properties of the cell wall were analyzed at different peripheral positions and heights in nine inclined, 12-year-old poplar (Populus×euramericana ‘Zhonglin46’) trees. The correlations between RLMS and wood properties were determined. The results showed that there were mixed effects of artificial inclination on wood quality and properties. The upper sides of inclined stems had higher RLMS, proportion of G-layer, bending modulus of elasticity, and elastic modulus of cell wall but lower microfibril angle than the lower sides. At heights between 0.7 m and 2.2 m, only the double wall thickness increased with height, RLMS and other wood properties such as fiber length and basic density fluctuated or changed littl...
Controlling the variability in mat structure and properties in bamboo scrimber (BS) is key to pro... more Controlling the variability in mat structure and properties in bamboo scrimber (BS) is key to producing the product for structural applications, and wide strip scrimber (WBS) is an effective approach. In this study, the effects of scrimmed bamboo bundle morphology and product density on the properties of WBS were investigated. WBS panels were manufactured and tested using wide (200 to 250 mm) bamboo strips with different fiberization intensity. Maximum strength properties (flexural, compressive, and shear strength), and lowest thickness swelling and water absorption were achieved with three or four passes due to the higher resin absorption by strips. For balanced product cost and performance, we recommend 1–2 fiberization passes and a panel density of 0.9–1.0 g/cm3. Panel mechanical properties were compared with other common bamboo composites. Bamboo scrimber products were highly variable in properties due to differing manufacturing processes, element treatments, and suboptimal mat ...
Numerous inorganic compounds were screened to identify those capable of minimizing the inhibitory... more Numerous inorganic compounds were screened to identify those capable of minimizing the inhibitory effect of Acacia mangium heartwood on the setting of cement. It was hypothesized that the most effective compounds would be ones that could accelerate the hydration of cement and form complexes with inhibitory phenolic extractives found in the heartwood of A. mangium. Our hypothesis proved correct since compounds such as SnCl4, AlCl3, and FeCl3 and/or their ionic species that were able to bond with the phenolic heartwood constituents of A. mangium as well as accelerate cement hydration were generally more effective at strengthening cement hydration in the presence of A. mangium heartwood than compounds that simply accelerated cement hydration. Compounds containing Ni2+, Ag+, Fe3+, and Co2+, that bonded to phenolic constituents of A. mangium heartwood, but lacked the ability to strongly accelerate cement hydration increased maximum hydration temperature attained in wood-cement mixes. The...
ABSTRACT Radiation shielding materials based on polymer or its composites require higher material... more ABSTRACT Radiation shielding materials based on polymer or its composites require higher material properties to endure the harsh radiation environments. In this investigation, electron beam (E-beam) irradiation and/or cross-linking agent triallyl cyanurate (TAC) were applied into the composites of a high density polyethylene (HDPE)/ethylene propylene monomer (EPM) blend containing B2O3 and/or PbO. The tensile strength increased as much as twice while the elongation enhanced more than 5 times by irradiation of 150 kGy with 10 MeV E-beam. Further enhancement of the tensile and elongation properties was achieved by applying both 1 wt.% TAC and E-beam irradiation, while use of 1 wt.% TAC alone decreased the mechanical properties. Flame retardancy of the polymer composites by mean of limit oxygen index (LOI) also achieved to higher than 21 without using any flame retardant additive.
Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a wat... more Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a water or alcohol-based dye at 20 °C, 75 °C or 90 °C for 72 h, followed by drying and coating with PF resin. Hot-pressed bamboo fiber composites (BFC) were manufactured, and the weathering performance of the composites made from dyed and natural bamboo material were tested over 90 days of the Autumn/Winter season in Beijing. Dye was able to penetrate the bamboo tissue to create a rich red color that degraded in color faster than BFC made from un-dyed bamboo. BFC made from un-dyed tissue remained a lighter but more consistent color over the weathering period. Dying the bamboo in ethanol-based dye was effective at pigmenting the product, but made it more susceptible to color degradation as well as greater mass and thickness loss due to the chemical degradation of the lignin caused by ethanol. Higher temperature of water dying treatment (90 °C) gave the greatest resistance to mass and thickness...
Current methods of reducing giant Moso bamboo (Phyllostachys pubescens Mazel) to elements for com... more Current methods of reducing giant Moso bamboo (Phyllostachys pubescens Mazel) to elements for composite manufacture are often inefficient and waste valuable biomass. This study employed geometric modelling to analyze and optimize the recovery of strands for oriented strand board manufacture. Three geometric models for calculating the numbers of strands, their widths, and their distribution based on culm diameter, wall thickness, target strand thickness, and flitch size were developed to determine an optimum slicing configuration. Real strands were produced by a disk flaker at the model strand thickness of 0.65 mm. Optimum configuration for the maximum number of usable strands per culm was from splitting culms into quarters, tight stacking, and radial slicing through the culm wall, which produced 37% more ‘usable’ strands 10 mm to 30 mm in width, fewer fines, and fewer excessively wide strands. Proportions of real strands fell into three size classes: 30 mm, and closely matched model...
In this work a simple rule of mixtures model to characterize the permeability of an OSB composite... more In this work a simple rule of mixtures model to characterize the permeability of an OSB composite as a function of fines contents and density is presented. Strands and fines in the core of the board are considered to lie between two extremes, either stacked in a series configuration (series model) or side by side in a parallel configuration (parallel model), with the permeability of the composite, K system , being a function of relative permeabilities of the series and parallel models. Equations for the permeability of these two configurations, K parallel and K series , are developed as functions of the known permeability of 100% strands, K s , and 100% fines, K f , and the mass fraction of fines, M f . Data on the permeability of the core of OSB compressed to three density classes and made with 0 and 100% fines content are used to determine the permeability of the parallel and series models, respectively. The series coefficient, α, which represents the contribution from the series ...
In the second paper in this series, we test the hypothesis that cement-setting accelerators with ... more In the second paper in this series, we test the hypothesis that cement-setting accelerators with the ability to chelate phenolic extractives will be more effective at improving the physical properties of wood-wool cement boards made from the heartwood of Acacia mangium than conventional accelerators. Furthermore, we assess whether the use of chelating accelerators will allow boards with acceptable properties to be manufactured from A. mangium wood-wool that has not been subjected to preliminary aqueous extraction to remove phenolic extractives. Batches of wood-wool from A. mangium containing approximately 75% heartwood were either soaked in water or used in their native form. The batches were then treated with an aqueous solution containing an inorganic compound (generally 0.05 or 0.1 M) selected for its ability to accelerate the hydration of Portland cement, and in the case of 5 of the 11 compounds tested, chelate phenolic extractives. Individual wood-wool cement boards were manufactured from each treated batch of wood-wool and tested for their dry and wet bending strength (MOR), stiffness (MOE), and water absorption properties. Boards made from untreated or water-soaked wood-wool acted as controls. The MOR and MOE of boards made from unsoaked A. mangium wood-wool and treated with the chelating accelerators tin or ferric chloride at 0.1 M concentration were 10.8 and 10.9 MPa and 2256 and 2178 MPa, respectively. These same boards showed less than 5% thickness swelling after 24-h immersion in water. In contrast most of the boards containing a conventional non-chelating accelerator had no structural integrity. The combination of a chelating accelerator and a conventional accelerator was particularly effective at improving the physical properties of boards made from unsoaked wood-wool. We conclude that wood-wool cement boards with acceptable physical properties can be manufactured from A. mangium heartwood by treating wood-wool with inorganic compounds that have the ability to chelate phenolic extractives and accelerate the hydration of Portland cement. Our findings could eliminate the need to pre-soak A. mangium wood-wool in water during the manufacture of wood-wool cement boards and may have broader relevance to the manufacture of wood-wool cement boards from other hardwood species containing phenolic extractives.
Retardancy and Mechanical Properties of Polylactic Acid with a Biodegradable Fire-Retardant Fille... more Retardancy and Mechanical Properties of Polylactic Acid with a Biodegradable Fire-Retardant Filler System Based on Bamboo Charcoal.
European Journal of Wood and Wood Products, May 3, 2015
This study is first in a series investigating the combination of Moso bamboo (Phyllostachys pubes... more This study is first in a series investigating the combination of Moso bamboo (Phyllostachys pubescens Mazel) and aspen (Populus tremuloides Michx.) to fabricate hybrid strand based panel composites. Here the wood and bamboo strands were evenly mixed together to form a thin, uni-directional strandboard 10 mm in thickness. The use of 30 % aspen strands was to improve the compaction and consolidation of the hard, uncompressible bamboo. The effects of replacing most of the aspen strands (70 %) with bamboo strands on board strength properties (IB, MOR, MOE) and moisture resistance were assessed. The effect of strands cut from the node free (internode) or node tissue portions of the culm on board properties was also systematically investigated. Substitution with 70 % internode Moso bamboo strands increased MOR by over 40 % compared with pure aspen and significantly lowered thickness swell and water absorption. Substituting aspen with the bamboo strands resulted in no change in MOE, in keeping with the tendency for natural Moso bamboo tissue to be high in bending strength and fracture toughness but lower in specific stiffness. The presence of node tissue in the bamboo strands significantly reduced the consolidation and mechanical properties of the composites.
... 1ANU Forestry, The Australian National University, ACT 0200, Australia. Email: Kate. Semple@ ... more ... 1ANU Forestry, The Australian National University, ACT 0200, Australia. Email: Kate. Semple@ anu. edu. ... 1989), result-ing in poor bonding in wood–cement composites. This is a major impediment to the use of A. mangium as a raw material for WWCB manu-facture. ...
Understanding maturation stress and wood properties of poplar tension wood are critical for impro... more Understanding maturation stress and wood properties of poplar tension wood are critical for improving lumber yields and utilization ratio. In this study, Released Longitudinal Maturation Strains (RLMS), anatomical features, physical and mechanical properties, and nano-mechanical properties of the cell wall were analyzed at different peripheral positions and heights in nine inclined, 12-year-old poplar (Populus×euramericana ‘Zhonglin46’) trees. The correlations between RLMS and wood properties were determined. The results showed that there were mixed effects of artificial inclination on wood quality and properties. The upper sides of inclined stems had higher RLMS, proportion of G-layer, bending modulus of elasticity, and elastic modulus of cell wall but lower microfibril angle than the lower sides. At heights between 0.7 m and 2.2 m, only the double wall thickness increased with height, RLMS and other wood properties such as fiber length and basic density fluctuated or changed littl...
Controlling the variability in mat structure and properties in bamboo scrimber (BS) is key to pro... more Controlling the variability in mat structure and properties in bamboo scrimber (BS) is key to producing the product for structural applications, and wide strip scrimber (WBS) is an effective approach. In this study, the effects of scrimmed bamboo bundle morphology and product density on the properties of WBS were investigated. WBS panels were manufactured and tested using wide (200 to 250 mm) bamboo strips with different fiberization intensity. Maximum strength properties (flexural, compressive, and shear strength), and lowest thickness swelling and water absorption were achieved with three or four passes due to the higher resin absorption by strips. For balanced product cost and performance, we recommend 1–2 fiberization passes and a panel density of 0.9–1.0 g/cm3. Panel mechanical properties were compared with other common bamboo composites. Bamboo scrimber products were highly variable in properties due to differing manufacturing processes, element treatments, and suboptimal mat ...
Numerous inorganic compounds were screened to identify those capable of minimizing the inhibitory... more Numerous inorganic compounds were screened to identify those capable of minimizing the inhibitory effect of Acacia mangium heartwood on the setting of cement. It was hypothesized that the most effective compounds would be ones that could accelerate the hydration of cement and form complexes with inhibitory phenolic extractives found in the heartwood of A. mangium. Our hypothesis proved correct since compounds such as SnCl4, AlCl3, and FeCl3 and/or their ionic species that were able to bond with the phenolic heartwood constituents of A. mangium as well as accelerate cement hydration were generally more effective at strengthening cement hydration in the presence of A. mangium heartwood than compounds that simply accelerated cement hydration. Compounds containing Ni2+, Ag+, Fe3+, and Co2+, that bonded to phenolic constituents of A. mangium heartwood, but lacked the ability to strongly accelerate cement hydration increased maximum hydration temperature attained in wood-cement mixes. The...
ABSTRACT Radiation shielding materials based on polymer or its composites require higher material... more ABSTRACT Radiation shielding materials based on polymer or its composites require higher material properties to endure the harsh radiation environments. In this investigation, electron beam (E-beam) irradiation and/or cross-linking agent triallyl cyanurate (TAC) were applied into the composites of a high density polyethylene (HDPE)/ethylene propylene monomer (EPM) blend containing B2O3 and/or PbO. The tensile strength increased as much as twice while the elongation enhanced more than 5 times by irradiation of 150 kGy with 10 MeV E-beam. Further enhancement of the tensile and elongation properties was achieved by applying both 1 wt.% TAC and E-beam irradiation, while use of 1 wt.% TAC alone decreased the mechanical properties. Flame retardancy of the polymer composites by mean of limit oxygen index (LOI) also achieved to higher than 21 without using any flame retardant additive.
Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a wat... more Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a water or alcohol-based dye at 20 °C, 75 °C or 90 °C for 72 h, followed by drying and coating with PF resin. Hot-pressed bamboo fiber composites (BFC) were manufactured, and the weathering performance of the composites made from dyed and natural bamboo material were tested over 90 days of the Autumn/Winter season in Beijing. Dye was able to penetrate the bamboo tissue to create a rich red color that degraded in color faster than BFC made from un-dyed bamboo. BFC made from un-dyed tissue remained a lighter but more consistent color over the weathering period. Dying the bamboo in ethanol-based dye was effective at pigmenting the product, but made it more susceptible to color degradation as well as greater mass and thickness loss due to the chemical degradation of the lignin caused by ethanol. Higher temperature of water dying treatment (90 °C) gave the greatest resistance to mass and thickness...
Current methods of reducing giant Moso bamboo (Phyllostachys pubescens Mazel) to elements for com... more Current methods of reducing giant Moso bamboo (Phyllostachys pubescens Mazel) to elements for composite manufacture are often inefficient and waste valuable biomass. This study employed geometric modelling to analyze and optimize the recovery of strands for oriented strand board manufacture. Three geometric models for calculating the numbers of strands, their widths, and their distribution based on culm diameter, wall thickness, target strand thickness, and flitch size were developed to determine an optimum slicing configuration. Real strands were produced by a disk flaker at the model strand thickness of 0.65 mm. Optimum configuration for the maximum number of usable strands per culm was from splitting culms into quarters, tight stacking, and radial slicing through the culm wall, which produced 37% more ‘usable’ strands 10 mm to 30 mm in width, fewer fines, and fewer excessively wide strands. Proportions of real strands fell into three size classes: 30 mm, and closely matched model...
In this work a simple rule of mixtures model to characterize the permeability of an OSB composite... more In this work a simple rule of mixtures model to characterize the permeability of an OSB composite as a function of fines contents and density is presented. Strands and fines in the core of the board are considered to lie between two extremes, either stacked in a series configuration (series model) or side by side in a parallel configuration (parallel model), with the permeability of the composite, K system , being a function of relative permeabilities of the series and parallel models. Equations for the permeability of these two configurations, K parallel and K series , are developed as functions of the known permeability of 100% strands, K s , and 100% fines, K f , and the mass fraction of fines, M f . Data on the permeability of the core of OSB compressed to three density classes and made with 0 and 100% fines content are used to determine the permeability of the parallel and series models, respectively. The series coefficient, α, which represents the contribution from the series ...
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