Volume 15 Issue 3

Eight groups of cellulose amorphous region models in which the mass fraction of water was separately 0%, 1%, 2%, 3%, 4%, 5%, 6%, and 7% were established using a molecular dynamics software material studio. The PCFF force field was selected to simulate the molecular dynamics of the model under the constant-pressure and constant-temperature (NPT) ensemble. The simulated temperature was set to 433.15 K. The experiment showed that the hydrogen bonds between cellulose chains affected the structure of cellulose, which led to the change of the end-to-end distance of the cellulose chain and the overall size of a cell. The diffusion degree of water molecules was closely related to the number of hydrogen bonds between cellulose and water. In the process of heat treatment of bamboo, the present simulation results suggest that the structure of bamboo may be damaged when the mass fraction of water vapor reaches or exceeds 7%.

Scots pine is one of the most commercially important wood species in Europe. This study assessed the potential usefulness of pinewood from the Noteć Forest for construction purposes by evaluating its mechanical properties and investigating the influence of the site conditions on the pinewood performance. Additionally, the variability of the mechanical properties from the bark to the pith was analyzed. The results showed that the properties of pinewood varied significantly within the Noteć Forest despite similar growing conditions, which may be a result of genetic variation. Wood from Sowia Góra had the greatest density (566 kg/m3) and excellent mechanical performance (compressive strength of 64 MPa), while wood from Zamyślin exhibited the lowest density (526 kg/m3) and a lower compressive strength (54 MPa). Comparison of the properties of the pinewoods from various locations indicated that the general conditions in the forest stand, however crucial for tree growth, were not the only determinants of wood performance. The results also showed high variability in density and mechanical properties between juvenile and mature wood in all the examined trees. Overall, pinewood from the poor habitats of the Noteć Forest could be a useful raw material for various industrial purposes.

Particleboard was produced by mixing oil heat-treated rubberwood particles at different ratios, with the goal of achieving high dimensional stability. Rubberwood particles were soaked in palm oil for 2 h and heat treated at 200 °C for 2 h. The treated particles were soaked in boiling water for 30 min to remove oil and were tested for chemical alteration and thermal characterization via Fourier-transform infrared spectroscopy and thermogravimetric analysis. Particleboard was fabricated by mixing treated rubberwood particles (30%, 50%, and 70%) with untreated particles (70%, 50%, and 30%, respective to previous percentages) and bonded with urea-formaldehyde (UF) resin. The results revealed that oil-heat treated particles had greater thermal stability than the untreated particles. The addition of oil heat treated particles improved the physical properties of the particleboard with no significant reduction in mechanical strength. However, this was only valid for ratios of 70% untreated to 30% treated and 50% untreated to 50% treated. When a ratio of 70% oil heat treated particles was used, both the physical and mechanical properties were reduced drastically, due to bonding interference caused by excessive oil content. Particleboard made with a ratio of 5:5 (treated to untreated) exhibited the best physical and mechanical properties.

Instead of compressing biomass into briquettes, this study considers the compression of biochar. Densification is necessary for biochar to increase bulk density for convenience of handling, transportation, and storage. Response surface methodology was employed, and briquetting of biochar from corn stover was carried out in this study to investigate the effects of moisture content (at levels of 16, 17.6, 20, 22.4, and 24%), pressure (at levels of 21.5, 25, 30, 35, and 38.5 MPa), and residence time (at levels of 4, 6.4, 10, 13.6, and 16 s), on crushing resistance, dimensional stability of briquettes, and specific energy consumption of briquetting. The results showed that the effects of the variables on each evaluation index were significant (P < 0.01), the influence order was obtained, and the regression models are set up. The optimum condition for the briquetting process was moisture content of 18.5%, pressure of 38.5 MPa, and residence time of 4 s, giving mean values of the briquette crushing resistance of 49.9 N, dimensional stability of 93.8%, and specific energy consumption of briquetting of 4.41 MJ/t, respectively. The errors between the predicted values and the experimental values are all less than 5%.

In view of environmental and economic issues, co-production technology with pulp as the major product is an important developmental direction in biorefinery. In this paper, high-yield pulp was prepared by hydrothermal pretreatment with controlled pH and subsequent mechanical refining using corn stover as raw material. By adding acetic acid or sodium hydroxide, the properties of the hydrolysate and the pulp were altered. Reducing the pH during hydrothermal pretreatment resulted in more cellulose and hemicellulose being released, while less lignin was released. Increased pH led to more lignin being released, while dissolution of carbohydrates did not change significantly. A maximum pulp yield at pH 5.84 of hydrolysate was obtained when 3.0% sodium hydroxide was used. The strength of pulp is highly related to the removal of lignin during hydrothermal pretreatment. The relationship between pH value in hydrothermal pretreatment and the physical properties of the pulp was established and could be further used for prediction and as guidance for process control. Moreover, the results could be used to develop technologies for industrial utilization of agricultural straw to co-generate fiber and other bio-based products.

The ability of Citrus limon (L.) Burm wood to be used for flooring applications was considered in this work. Selected wood properties were determined, and the response to weathering was tested. Janka hardness, density, screw withdrawal resistance, color, glossiness, and artificial weathering (144, 288, and 432 h) were determined. The wood from Citrus limon was shown to be a dense wood with air density around 830 kg/m3 and with a high Janka hardness of 138.0 N/mm2, 120.4 N/mm2, and 115.9 N/mm2 for cross, tangential, and radial sections, respectively. This opens good perspectives to this kind of wood being used for flooring. Statistical analysis showed that both Janka hardness and screw withdrawal resistance were significantly different between surfaces. Nevertheless, the homogeneity groups showed that the main differences were between the surfaces in the longitudinal direction when compared with the transverse direction. The wood is lighter than most common woods and it is mainly yellow. After weathering, the wood became darker, redder, and yellower. Glossiness decreased in the first hours of the weathering period.

Wood permeability has a major effect on industrial wood processing and utilization. Wood anatomy and resin influence the permeability of wood. Understanding and manipulating these influences is important to optimize the manufacture and use of forest products. This study investigated the relationships between wood anatomical traits, radial permeability, and resin content of samples collected from 19-year-old hybrid pines (Pinus elliottii var. elliottii × Pinus caribaea var. hondurensis) from Queensland, Australia. The earlywood tracheid tangential lumen diameter and axial resin canal diameter were statistically positively correlated with radial permeability. The heartwood proportion and the frequency of axial resin canals were statistically negatively correlated with radial permeability and positively correlated with resin content. The axial resin canal diameter, sapwood proportion, latewood content, ray frequency, and earlywood tracheid lumen diameter increased from pith to bark, whereas the axial resin canal frequency decreased. Resin was found distributed throughout the wood microstructure, from pith to bark in many samples, and in both heartwood and sapwood. However, there was a much greater quantity of resin in heartwood and wood from the middle (inner radius) of the tree, with widespread occurrence of resin impregnation in the axial tracheids.

The objectives of this study were to evaluate the current dust extraction efficiency used in the Malaysian furniture industry and also the effectiveness of using engineered nanoparticle (ENP)-added coatings to reduce dust emission in the wood finishing operation. This study was in response to the enforcement of the Clean Air Regulation (2014), which requires significant improvements in the air quality and the work environment in the wood-based industry in Malaysia. A series of sanding experiments with different abrasive grit sizes and different coating types were conducted to determine the dust emission levels. The results suggested that higher capture velocity of 30 m/s was necessary to effectively capture the wood coating dust emitted. Further, ENP-added wood coatings did not differ markedly from conventional coatings with regard to dust emission characteristics. The study also revealed that total dust concentration had an inverse relationship, while the amount of finer dust particles was linearly related to the coating film hardness. Therefore, to comply with the Clean Air Regulation, the Malaysian furniture industry needs to significantly improve its dust extraction system.

Lignin and cellulose were separated from eucalyptus wood powder by partial liquefaction in deep eutectic solvents (DESs). Approximately 97.4% of the original lignin in the eucalyptus wood was separated and recovered with a choline chloride-PEG 200 mixture. Lignin purity that was as high as 99% could be achieved by this separation method. The DES that was comprised of choline chloride, PEG 200, and glycerin could be used to separate the cellulose. The purity and the crystallinity of the isolated cellulose were as high as 92% and 73%, respectively. Experimental data showed that the examined DES systems could effectively separate the constituents of eucalypt wood powder.

In this work, a toy was developed from bleached sulphate pulp via a moulded fibre production technique. Moulded fibre products are generally used to preserve main products from damage during transportation and stow them in a particular order. This work investigated the use of moulded fibre products in daily life as final products. Bleached softwood sulphate pulp was used for the experiments to avoid the potential hygiene problems of using recycled paper for toy production. The physical properties of different degrees of refined sulphate pulp were evaluated during toy sample production. The results indicated that toys produced with bleached softwood sulphate pulp had optimum compression strength (22 kpgf) at the 35 SR° freeness level. Produced prototypes satisfied EN 71-3:2013+A1(2014) in terms of migration element limits.