Volume 11 Issue 2

The interaction among three biomass components (hemicellulose, cellulose, and lignin) in an autoclave was studied based on the extreme vertices of a constrained region that had a significant effect on the distribution and characteristics of the products. The mathematical model of the three components was established according to the yield distribution. Based on the model, the biomass components and the hydrothermal characteristics of biomass were predicted. Subsequently, the contents of the main biomass components were analyzed, thus eliminating the complicated testing process and providing a convenient and reliable calculation tool for determining the three biomass components. The gaseous products showed that products from cellulose hydrolysis promoted hemicellulose hydrolysis and generated large amounts of CO2. The lignin content, as well as the low cellulose and hemicellulose contents, inhibited the acids and ketones in light oil. In addition, the interaction among cellulose, hemicellulose, and lignin inhibited the production of acids in heavy oil and promoted phenolic synthesis. A series of hydrolysis product reactions such as polymerization and condensation were increased to produce a char at a high degree of aromatization by the interaction among the three components.

The crystallinity and acoustic-vibration parameters of Picea jezoensis, including specific Young’s modulus (E/ρ)coefficient of sound-radiation resistance (R), sound resistance (ω), and the ratio of Young’s modulus to the dynamic stiffness modulus (E/G), before and after heat treatment were measured and characterized. Conditions for the heat treatment included N2 as the protection gas and temperatures of 170 °C, 190 °C, and 210 °C with holding times of 2 h, 3 h, and 4 h. The results showed that specific Young’s modulus, the coefficient of sound-radiation resistance, and the ratio of Young’s modulus to the dynamic stiffness modulus ncreased, whereas sound resistance decreased, thereby improving the acoustic performance of the wood. The maximum increments were 5.7% for specific Young’s modulus (210 °C, 3 h), 8.8% for the coefficient of sound-radiation resistance (210 °C, 3 h), and 13.8% for the ratio of Young’s modulus to the dynamic stiffness modulus (210 °C, 4 h). Conversely, the maximum decrease in sound resistance was 5.6% (170 °C, 2 h). The crystallinity of heat-treated samples universally increased, and the maximum reached 60.67% (210 °C, 4 h), which was 9.9% higher than that of the control group. Moreover, the sound resistance decreased within increasing crystallinity growth, indicating that these two parameters were negatively correlated. Overall, the acoustic-vibration performance of P. jezoensis was improved through heat treatment, with the best vibration performance obtained at 210 °C with a holding time of 4 h.

Transforming waste or recycled materials into value-added products is of high priority today. Wood plastic composites (WPCs) show high potential for the use of recycled materials in making durable composites. The applicability of WPC panels produced from recycled materials (ultralight foam core particleboards) for exterior building application was tested using wood-destroying basidiomycetes. The results showed that the panels were fully resistant against Coniophora puteana (Cp) and Gloeophyllum trabeum (Gt), but not very resistant against Pleurotus ostreatus (Po). The decay susceptibility index of Po-exposed specimens showed that the polystyrene-bonded (PS) samples were more resistant than solid beech wood samples that were used as references, followed by melamine-urea formaldehyde-bonded samples. A comparison with the reference samples also showed that the panel density had a significant influence on the panel’s resistance against basidiomycetes. The higher the panel density, the more resistance will be achieved in the panel.

Pulp properties are key factors to assessing the performance of a refining process, evaluating operational conditions, and optimizing the process of stock preparation. This paper presents a data-driven approach to estimate the beating degree and wet weight of pulp after refining using case-based reasoning (CBR). Historical data generated in a refining process at a paper mill was used to evaluate the proposed model. The root mean square error (RMSE) and coefficient of variance of the root mean square error (CV-RMSE) of the beating degree estimation results in CBR were 1.30 and 4.32%, respectively, and the RMSE and CV-RMSE of the wet weight were 0.50 and 19.09%, respectively. The results of beating degree prediction were satisfactory, and the results of wet weight were also acceptable. To test the performance of CBR model, support vector machine algorithm (SVM) were employed to verify the effectiveness and accuracy. The RMSE and CV-RMSE of the beating degree estimation results in SVM were 1.20 and 4.02%, respectively, and the RMSE and CV-RMSE of the wet weight were 0.44 and 16.73%, respectively. As a result, the proposed model was as accurate as the SVM method.

The use of wood in outdoor, above-ground applications is increasing in Europe. To further increase wood usage, more information related to service life and maintenance costs must be provided. Water exclusion efficacy (WEE) is one of the most important factors influencing service life and strongly correlates to wood moisture dynamics, surface properties, and hydrophobicity (WEE as a whole). WEE can be improved with modifications and hydrophobic treatments. The aim of this study was to elucidate which wood surface properties affect WEE and to note changes over time caused by artificial or natural aging. Wood samples of oak (Quercus), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies), and beech (Fagus sylvatica) were used to investigate this phenomenon. The moisture performance of the wood samples was improved with thermal modification, wax, oil, and biocide treatment. In total, 17 materials were prepared. After treatment, four different aging procedures were applied. Before and after aging, Fourier transform infrared spectra, colour, and contact angle were determined. The analysis of untreated wood based materials indicated that durability and hydrophobicity are related. Of all the treatments, wax performed the best and retained high hydrophobicity even after the most severe aging method (outdoor exposure).

The impact of montmorillonite (nanoclay) addition on the mechanical and morphological properties of paper made from neutral sulfite semichemical (NSSC) and old corrugated container (OCC) pulps was evaluated in systems utilizing cationic starch for dry-strength. The nanoclay amount was considered at five levels, and cationic starch was applied at a 1% level. In OCC pulp, by increasing the nanoclay up to 4%, the tensile index and corrugating medium test (CMT) were increased; however, there was a decrease when the nanoclay was increased to 8%. By increasing the nanoclay to 2%, the tear and burst indexes and ring crush test (RCT) increased, but there was a reduction when the nanoclay was increased to 8%. Average air resistance tended to increase as the nanoclay was increased to 8%. In the case of NSSC pulp, by increasing the nanoclay amount from 0 to 8%, the average tensile, tear, and burst indexes decreased, while the air resistance increased. The CMT amount increased with increasing nanoclay content to 2%, but a reduction was seen for other levels. The RCT exhibited an increase with increasing nanoclay up to 4%, after which it decreased. Results suggest that the proportion of nanoclay added with cationic starch needs to be optimized, depending on furnish conditions.

This study investigated the effects of felling season on the discoloration of rubberwood sawn timber during conventional kiln drying. The samples were collected throughout the year 2015 to monitor the variation of free sugars and starch content in the rubberwood logs. Two batches of logs, one from the rainy season and the other from the dry season, were felled and sawn for experimentation. The findings showed that discoloration was more prominent in sawn timber obtained from logs felled during the dry season. The amount of free sugars and starch in the logs had a strong influence on the extent of discoloration in the rubberwood sawn timber during the kiln drying process. A higher amount of free sugars and starch in the logs felled during the dry season increased the incidence of blue stain on these logs. The results of this study conclusively showed that discoloration in rubberwood can be minimized by the choice of log felling season and the use of an appropriate drying technique, which will inevitably improve the aesthetic appeal of the wood.

Laccase enzyme was used as a pretreatment agent to delignify empty fruit bunches (EFB) for sugar production. The degree of delignification of the biomass was assessed directly by the percentage of pre-pretreatment weight loss (%) after pretreatment and indirectly by the amount of total sugar produced after saccharification of the pretreated biomass with cellulase enzymes. Process parameters such as pretreatment time, temperature, enzyme concentration, substrate concentration, pH, and substrate size were studied using a one-factor-at-a-time (OFAT) analysis. The combined effect of temperature and pH on the pretreatment was studied using the face-centered central composite design (FCCCD) of response surface methodology (RSM). The optimized conditions for EFB pretreatment using laccase enzyme were achieved as follows: sample size, 2 mm; temperature, 25 °C; time, 4 h; substrate concentration, 5% (w/v); pH 5; and enzyme concentration, 20 IU/g of EFB. Although higher pretreatment was achieved with substrates of 1 mm size and at a temperature of 35 °C, these conditions were not considered energetically sustainable because of the need for energy during milling for sample size reduction and energy for temperature maintenance at 35 °C.

Paper performance qualities strongly depend on the origin of cellulose fibers. Awareness of environmental issues and sustainable development has led to the increase in the use of recycled printing papers. Recovered fibers are often used as a substitute for virgin wood fibers in the production of certain types of papers. As recovered fibers cannot provide the same quality level of paper products as virgin wood fibers, alternative sources of virgin cellulose fibers need to be identified. The aim of this research was to analyze the printability of laboratory papers made of different contents of straw pulp. Therefore, the printing papers were formed using straw pulp of three different cereal species (wheat, barley, and triticale) and mixing them with recycled newsprint in different weight ratios. The printability of these laboratory papers was analyzed by classifying dot reproduction quality based on four dot reproduction attributes. Printed dot reproduction greatly affects the quality of reproduction in graphic products, as dots are the most important element in multi-color reproduction of texts and images. It was confirmed that laboratory papers containing straw pulp provide the same or even better dot reproduction quality than laboratory control papers formed only of recycled newsprint.

B-Zn-Si-Al compounds are modified Si-Al compounds made of sodium silicate, zinc sulfate, borax, and aluminum sulfate. They act as a fire retardant during the preparation of ultra-low density fiberboards (ULDFs). An orthogonal experiment was used to optimize the contents of the four compounds according to the limiting oxygen index. Fourier transform infrared spectroscopy was employed to preliminarily analyze the chemical structure of the compounds. Additionally, a cone calorimeter was used to assess the fire performance of the ULDFs. The results suggested that the optimized solution was made of 27.0 mL of sodium silicate solution, 27.0 mL of aluminum sulfate solution, 3.0 g of zinc sulfate, and 6.5 g of borax, resulting in an oxygen index of 29.5%. The bond Al-O-B was detected at 1397 and 796 cm-1. The Si-O-Zn bonds were detected at 867 cm-1. The heat release rate, total heat release, and total smoke release decreased and the mass residual ratio increased in the sample using the optimal conditions from the orthogonal array design. It was concluded that B-Zn-Si-Al compounds effectively protect fibers from fire.