Effect of CaCO3 on the wood properties of tropical hardwood species from fast-growth plantation in Costa Rica

This work aimed to evaluate the effect of the precipitation of CaCO3 via subsequential in-situ mineral formation based on a solution-exchange process of two solution-exchange cycles via impregnation with CaCl2 in ethanol and NaHCO3 in water. The effects were investigated in terms of the structure of the wood and the thermal, physical, mechanical, and decay resistance properties of nine species commonly used in commercial reforestation in Costa Rica. The thermogravimetric analysis results showed that the woods with the highest formation of CaCO3 showed a more pronounced signal at 200 °C in relation to untreated/wood; therefore, they were more thermostable. The fire-retardancy test showed that flame time in CaCO3/wood composites was longer than for untreated/wood in half of the species tested, presenting a positive effect of mineralization. Wood density, decay resistance, modulus of rupture (MOR), modulus of elasticity (MOE) in flexion, and MOR in compression were slightly affected by mineralization. Water absorption increased, but it had no negative effect on the dimensional stability. In general, mineralization can be a chemical treatment to increase the dimensional stability and fire resistance of hardwood species without modifying the wood’s physical and mechanical properties.

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Structure and Property of PGMA/Wood Composite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.87-88.456 ◽

2009 ◽

Vol 87-88 ◽

pp. 456-461 ◽

Cited By ~ 2

Author(s):

Yong Feng Li ◽

Yi Xing Liu ◽

Jiang Tao Shi ◽

Gang Li

Keyword(s):

Mechanical Properties ◽

Dimensional Stability ◽

Cell Walls ◽

Cellular Structure ◽

Untreated Wood ◽

Decay Resistance ◽

Modulus Of Rupture ◽

Test Results ◽

Tight Contact ◽

Wood Based Composite

In order to prepare a wood-based composite material which, as a type of multifunctional and natural bio-based material, possesses satisfactory mechanical properties, excellent durability (i.e., decay resistance and dimensional stability), and Aenvironmental characteristic, the study presents a new method which is based on the cellular structure of wood by initiating polymerizable monomers for in situ polymerization. Glycidyl methacrylate (GMA) as a multifunctional and polymerizable monomer was chosen, and impregnated into the porous structure of wood. After a thermal-catalyst process, the wood-based composite, PGMA/Wood, was prepared. The structure of this material was analyzed by SEM, FTIR and XRD; and its performance was also determined. The analyzing results show that GMA not only polymerized in the cellular structure in a solid form and amorphous form, which fully and uniformly filled in wood cell lumen, but also sufficiently grafted onto wood cell walls in a chemical level, resulting in tight contact between wood cell walls and resultant polymers (PGMA) without any obvious cracks. The test results of mechanical properties show that the modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and hardness of PGMA/Wood increased by 82%, 122%, 139%, and 348% over those of untreated wood, respectively. The test results of durability show that the dimensional stability and decay resistance of PGMA/Wood improved 44% and 91% than those of untreated wood, respectively. Such composite could be widely applied in the fields of construction, furniture and traffic.

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Effect of Moderate Temperature Thermal Modification Combined with Wax Impregnation on Wood Properties

Applied Sciences ◽

10.3390/app10228231 ◽

2020 ◽

Vol 10 (22) ◽

pp. 8231

Author(s):

Jing-Wen Zhang ◽

Hong-Hai Liu ◽

Lin Yang ◽

Tian-Qi Han ◽

Qin Yin

Keyword(s):

Mechanical Strength ◽

Dimensional Stability ◽

Color Change ◽

Strength Loss ◽

Wood Properties ◽

Thermal Modification ◽

Moderate Temperature ◽

Modulus Of Rupture ◽

Internal Surfaces ◽

Higher Temperature

Thermal modification (TM) improves the hydrophobicity, dimensional stability, and durability of wood, but TM commonly results in severe color change and mechanical strength loss as wood is treated at higher temperature. In this study, Pterocarpus macrocarpus Kurz wood was thermally modified at moderate temperature (150 °C) and higher temperature (200 °C), and subsequently TM wood at 150 °C was subjected to wax impregnation (WI), the effect of a combination of TM and WI on the hygroscopicity, dimensional stability, and mechanical properties, as well as the micro-structure of wood, were investigated and compared. The results showed that the mass loss of wood was slight at 150 °C TM, while it became severe at 200 °C TM conditions. TM conditions affected the amount of the subsequent wax impregnation; the equilibrium moisture content (EMC), water absorption ratio, and adsorption and absorption swelling of the 150 °C TM + WI group were lower than that of 200 °C TM, and presented the lowest value. Moderate temperature TM could improve the hydrophobicity and dimensional stability of wood, but WI played a key role in the improvement. TM decreased the modulus of rupture (MOR) of wood, while WI improved the MOR. TM increased the modulus of elasticity (MOE) of wood, but WI had little effect on MOE; Scanning electron microscope (SEM) observation showed that the wax was successfully impregnated into the wood interior, and presented an even distribution on the internal surfaces of wood cells; Fourier-transform infrared spectroscopy (FTIR) spectra verified the changes of –OH and C=O after TM and TM + WI, which contributed to decreasing hygroscopicity and improving the dimensional stability of the wood. Impregnated wax improved wood mechanical strength, but decreased the lightness, and deepened the color of wood. The combination of thermal modification at moderate temperature with subsequent wax impregnation is a practical approach for improving wood properties.

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The Improvement of Durability of Marine Wood with Polymer and its Mechanism

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1021 ◽

2009 ◽

Vol 79-82 ◽

pp. 1021-1024 ◽

Cited By ~ 1

Author(s):

Yong Feng Li ◽

Yi Xing Liu ◽

Xiang Ming Wang ◽

Xiu Rong Li

Keyword(s):

Porous Structure ◽

Dimensional Stability ◽

Cell Walls ◽

Treated Wood ◽

Untreated Wood ◽

Decay Resistance ◽

Hydroxyl Group ◽

Alkali Resistance ◽

Hydroxyl Groups ◽

Marine Corrosion

In order to improve the durability of marine wood against the long-term marine corrosion, the study explores to use two bifunctional reagents, maleic anhydride (Man) and glycidyl methacrylate(GMA), to react with wood by impregnating them into the porous structure of wood and further initiating them to polymerize with an initiator, AIBN, through a heat process. After the above modification, the durability of the marine wood treated with polymer was tested, and its mechanism was further analyzed as well. The testing results of the durability show that the acid resistance, the alkali resistance, the decay resistance against marine borers and the dimensional stability of the treated wood increases by 2.02 times, 12.39 times, 4.96 times and 3 times over untreated wood, respectively; and its Anti Swelling Efficiency (ASE) for dimensional stability reaches 53%, which almost equals the value of the wood treated by PEG-1500 under the same condition, while its leachability resistance is greatly higher than wood treated by PEG-1500. The analysis result with FTIR indicates that Man and GMA both react with wood, and Man reacts with the hydroxyl group of wood cell walls by its anhydride group, and GMA polymerizes in the porous structure of wood. The charactering result with SEM reveals that the resultant polymer fills in wood cell lumina as a solid form, which contacts tightly the wood cell walls without obvious gaps. The greatly reducing amount of hydroxyl groups after the reaction and the heavy jamming channels for water and marine borers approaching to wood cell walls both contribute to the improving durability of the modified wood.

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New Perspective on Wood Thermal Modification: Relevance between the Evolution of Chemical Structure and Physical-Mechanical Properties, and Online Analysis of Release of VOCs

Polymers ◽

10.3390/polym11071145 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1145 ◽

Cited By ~ 7

Author(s):

Jiajia Xu ◽

Yu Zhang ◽

Yunfang Shen ◽

Cong Li ◽

Yanwei Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Dimensional Stability ◽

Chemical Structure ◽

Low Cost ◽

Physical And Mechanical Properties ◽

Decay Resistance ◽

Thermal Modification ◽

Infrared Spectrometry ◽

Dominant Component ◽

New Perspective

Thermal modification (TM) is an ecological and low-cost pretreated method to improve the dimensional stability and decay resistance of wood. This study systematically investigates the relevance between the evolution of chemical structure and the physical and mechanical properties during wood thermal modification processes. Moreover, the volatility of compounds (VOCs) was analyzed using a thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGA-FTIR) and a pyrolizer coupled with gas chromatography/mass spectrometer (Py-GC/MS). With an increase of TM temperature, the anti-shrink efficiency and contact angle increased, while the equilibrium moisture content decreased. This result indicates that the dimensional stability improved markedly due to the reduction of hydrophilic hydroxyl (–OH). However, a slight decrease of the moduli of elasticity and of rupture was observed after TM due to the thermal degradation of hemicellulose and cellulose. Based on a TGA-FTIR analysis, the small molecular gaseous components were composed of H2O, CH4, CO2, and CO, where H2O was the dominant component with the highest absorbance intensity, i.e., 0.008 at 200 °C. Based on the Py-GC/MS analysis, the VOCs were shown to be mainly composed of acids, aldehydes, ketones, phenols, furans, alcohols, sugars, and esters, where acids were the dominant compounds, with a relative content of 37.05−42.77%.

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Physical and Mechanical Properties of Five Heat-Treated Hardwood Species

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.472-475.1132 ◽

2012 ◽

Vol 472-475 ◽

pp. 1132-1134

Author(s):

Jin Sun ◽

Xiao Bo Wang ◽

Xiao Jing Wang ◽

Yan Lin ◽

Zhen Zhong Gao

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Dimensional Stability ◽

Negative Impact ◽

Physical And Mechanical Properties ◽

Betula Platyphylla ◽

Fraxinus Mandshurica ◽

Hardwood Species ◽

Heat Treated ◽

Betula Platyphylla Suk

Five hardwood species (Schima superba Gardn, kapur( Dryobalanops sp.), ash (Fraxinus mandshurica Rupr.), birch(Betula platyphylla Suk.), tauari (Couratari sp.)) were conducted the Heat treatment at 185°C.. The results indicated that the dimensional stability, modulus of elasticity (MOE) increased greatly while the wettability decreased after treatment. There was a negative impact of heat treatment on MORs.

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Selected Physical and Mechanical Properties of Microwave Heat Treated Rubberwood (Hevea brasiliensis)

Applied Sciences ◽

10.3390/app10186273 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6273

Author(s):

Aujchariya Chotikhun ◽

Jitralada Kittijaruwattana ◽

Emilia-Adela Salca ◽

Salim Hiziroglu

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Electron Microscope ◽

Dimensional Stability ◽

Hevea Brasiliensis ◽

Physical And Mechanical Properties ◽

Modulus Of Rupture ◽

Heat Treated ◽

Temperature Levels ◽

Microwave Heat

The objectives of this study were to evaluate some of physical and mechanical properties of rubberwood (Hevea brasiliensis) as function of microwave heat treatment process. The specimens were heat treated at three temperature levels of 150 °C, 180 °C, and 220 °C for 20 min in a small microwave oven connected to a computer. Bending characteristics, namely modulus of elasticity (MOE), modulus of rupture (MOR) as well as hardness of the samples were tested. Dimensional stability in the form of swelling and water absorption of the specimens were also determined. Based on the findings in this work it appears that microwave can be used successfully for heat treatment of rubberwood. Overall mechanical properties of the samples were adversely influenced by the treatment. MOE, MOR and hardness values of the samples treated at a temperature of 220 °C had 2.37, 3.69, and 2.12 times reduced than those of control samples, respectively. Dimensional stability of the heat treated samples as a result of 2-h and 24-h water soaking improved. Micrographs take from scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed that certain amount of damage took place in the cellwall of the treated specimens. Overall discoloration on the samples due to microwave heat treatment was found insignificant.

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Bamboo hybrid laminate board (Gigantochloa apus) strip with falcata veneer (Paraserianthes falcataria) in selected fiber directions

BioResources ◽

10.15376/biores.15.4.9228-9242 ◽

2020 ◽

Vol 15 (4) ◽

pp. 9228-9242

Author(s):

Ihak Sumardi ◽

Rudi Dungani ◽

Ignasia Maria Sulastiningsih ◽

Deaul Aulia

Keyword(s):

Mechanical Properties ◽

Dimensional Stability ◽

Urea Formaldehyde ◽

Physical And Mechanical Properties ◽

Modulus Of Rupture ◽

Core Material ◽

Fiber Direction ◽

Paraserianthes Falcataria ◽

Low Dimensional ◽

Hybrid Laminate

This study investigated the physical and mechanical properties of bamboo hybrid laminate boards (BHLB) in various fiber directions as a potential wood-replacement structural material. This study used dry bamboo (Gigantochloa apus) processed into thin strips with a thickness of 4 mm and falcata veneer (Paraserianthes falcataria). The BHLB were arranged based on different fiber directions (i.e., perpendicular and parallel) in cold pressing (30 min; 22.2 kgf/cm2) and hot pressing (6 min; 15 kg/cm2). The adhesive used was urea-formaldehyde (UF) resin (glue spread rate of 250 g/m2 and inter veneer 170 g/m2). Physical and mechanical properties were observed to validate the feasibility of preparing BHLB from bamboo strips and falcata veneers. The results showed that the arrangement of the fiber direction affects dimensional stability, MOE (modulus of elasticity), MOR (modulus of rupture), shear strength, and screw withdrawal strength. Falcata veneer as the board core material resulted in lower density, low dimensional stability, and higher water absorption. However, the mechanical properties were not much different and fulfilled the standard for structural use. This study concludes that bamboo can be used for making composite BHLB as an alternative to wood-based composites for structural use.

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Effect of thermo-hydro-mechanical densification on the wood properties of three short-rotation forest species in Costa Rica

BioResources ◽

10.15376/biores.15.4.8065-8084 ◽

2020 ◽

Vol 15 (4) ◽

pp. 8065-8084

Author(s):

Carolina Tenorio ◽

Roger Moya

Keyword(s):

Costa Rica ◽

Color Change ◽

Initial Density ◽

Maximum Load ◽

Wood Properties ◽

Modulus Of Rupture ◽

Densified Wood ◽

Normal Wood ◽

Densification Process ◽

Short Rotation

Alnus acuminata, Vochysia ferruginea, and Vochysia guatemalensis are three low-density wood species used for reforestation in Costa Rica. The goal of this work was to study a thermo-hydro-mechanical densification process and test the characteristics of densified wood of these species. Twelve densifying treatments based on temperature, compression time, and use/no use of steam were tested. The variables of the densification process and the properties of the densified wood were determined. The results showed that the densification percentage was over 80% for wood of A. acuminata and over 70% for wood of V. ferruginea and V. guatemalensis. In the three species, the densification process was influenced by initial density. The influence of temperature during the densification process affected the heating rate and color change. An increase in the modulus of elasticity and modulus of rupture in static bending and in the hardness of the densified wood relative to the normal wood was observed, as well as a clear positive correlation of the properties with final density and maximum load, the latter being highly correlated with initial density. This showed that initial density was significant in the densification process and affects wood properties.

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DECAY RESISTANCE, DIMENSIONAL STABILITY AND MECHANICAL STRENGTH OF POPLAR WOOD MODIFIED WITH PLANT-DERIVED COMPOUNDS

Wood Research ◽

10.37763/wr.1336-4561/66.4.556568 ◽

2021 ◽

Vol 66 (4) ◽

pp. 556-568

Author(s):

JIAPENG WANG ◽

ZHENJU BI ◽

ZHANGJING CHEN ◽

LI YAN ◽

YAFANG LEI

Keyword(s):

Mechanical Properties ◽

Citric Acid ◽

Dimensional Stability ◽

Color Change ◽

White Rot Fungi ◽

Brown Rot ◽

Decay Resistance ◽

White Rot ◽

Modulus Of Rupture ◽

Weight Percentage

The cinnamaldehyde, salicylic acid, stearolic acid and citric acid were plant-derived organic compounds that can be activated to fungi, that could degrade the wood in long term. The compounds with concentrations of 3%, 5% and 7% assisted by different dispersants were impregnated into poplar (Populus nigra L.) specimens by the vacuum-pressure method. After that, weight percentage gain (WPG), decay resistance against white-rot fungi (Trametes versicolor) and brown-rot fungi (Gloeophyllum trabeum), color change, dimensional stability and mechanical properties including modulus of elasticity (MOE) and modulus of rupture (MOR) were measured. The results indicated that cinnamaldehyde impregnated poplar showed antifungi activity against both G. trabeumand T. versicolor, and citric acid impregnated poplar showed antifungi activity against G. trabeum. The color of poplar specimens before and after impregnated cinnamaldehyde and citric acid had a little change, dimensional stability had been improved and mechanical properties especially for MOR increased significantly.

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Performance of Wood-Polymer Composite Prepared by In Situ Polymerization of Styrene

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.26-28.181 ◽

2010 ◽

Vol 26-28 ◽

pp. 181-185 ◽

Cited By ~ 1

Author(s):

Yong Feng Li ◽

Xin Meng ◽

Jian Li ◽

Yi Xing Liu

Keyword(s):

Mechanical Properties ◽

Polymer Composite ◽

Untreated Wood ◽

Decay Resistance ◽

Modulus Of Rupture ◽

Interior Decoration ◽

Wood Polymer ◽

New Material ◽

Wood Polymer Composite

A new material was prepared by formation of polystyrene in situ wood porous structure from styrene monomer through thermal-catalyst treatment. And the performance of such wood-polymer composite, containing mechanical properties and durability, was also tested. The SEM results showed that polymer was generated inside wood, and filled in wood cellular structure. The mechanical properties of such wood-polystyrene composite including modulus of rupture (MOR), modulus of elasticity (MOE), compression strength and hardness, were respectively improved 38%, 77%, 21% and 97% over untreated wood. And the durability of the novel composite involving dimensional stability, decay resistance and stability against weather erosion were remarkably improved than those of untreated wood. Such composite can be widely used in fields of construction, traffic and interior decoration, which greatly enhanced the utilization of low-valued wood material instead of high-quality wood.

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