Volume 16 Issue 4

The viscoelasticity of Taxodium hybrid ‘Zhongshanshan’ wood, while undergoing hydrothermal processing, was investigated via dynamic thermomechanical analysis. The results showed that the elastic deformation and viscous deformation of the Taxodium hybrid ‘Zhongshanshan’ heartwood were greater than the sapwood. The heartwood average storage modulus and average loss modulus were greater than the sapwood. The difference between the heartwood and sapwood had little effect on the average glass transition temperature of their hemicellulose, which was approximately 74 °C. The radial average storage modulus was greater than the tangential, and the difference between the average loss modulus in the radial and tangential directions was negligible. The average glass transition temperature in the radial direction was slightly lower than the tangential direction. As the moisture content increased, the average storage modulus and its average hemicellulose glass transition temperature decreased. The average glass transition temperature tended to be lower as the moisture content increased. This study revealed the structural deformation and molecular movement of Taxodium hybrid ‘Zhongshanshan’ wood, while undergoing hydrothermal processing; this has important theoretical value for understanding its characteristics as well as its rational and efficient usage.

Paper, or a pulp fiber sheet, is biodegradable and it can be a promising alternative to plastics, thus avoiding a serious form of marine pollution. However, its degradability in marine environments has not been well studied. This study investigated how a network of pulp fibers disintegrates in seawater compared with soil. Samples of pulp fiber sheets were exposed to seawater and soil for 4 months under stationary conditions at 25 °C. Digital photo images and scanning electron microscopy (SEM) images were used for morphological and color change investigations, while Fourier transform infrared (FT-IR) analysis was used to compare the chemical components of the samples before and after degradation. The area of the sample decreased by 22.3% in the seawater. The degradation rate in seawater was much lower than in the soil. The degradation mechanism in seawater was different from that in the soil because of the different microorganisms in each environment.

In the process of the “green revolution”, individuals have realized the importance of recycling waste materials. However, with ongoing individual changes in lifestyle, the huge resource of discarded wooden furniture is still considerably underutilized. This paper aims to provide new ideas for the recycling of discarded wooden furniture and to create added value to used furniture. Based on the summarization of existing recycling technology and methods, the diversified innovation and reuse of discarded wooden furniture integrating the current aesthetic and demand of people from multiple aspects are analyzed for the purpose of revealing the hidden value of waste materials. Waste recycling is of great importance to the country and enterprises in line with the concept of circular economy. For the sake of further excavating the hidden value of discarded wooden furniture products, the additional in-depth research in optimizing and upgrading green production and manufacturing in furniture industry is called for in the paper.

Nanocellulose (NC) was isolated from an underutilized agricultural residue, defatted rice bran (DRB), obtained from three major paddy varieties in Malaysia, MARDI Rice (MR): MR 220, MR 219, and MR 297. The DRB was subjected to alkali (NaOH) and bleaching treatments prior to the isolation of NC. The NC from DRB was produced through the acid hydrolysis technique using 55%wt sulphuric acid (H2SO4) with the assistance of ultrasonication. The morphological structure of NC was analyzed through transmission electron microscopy (TEM). Based on the observation, a needle-like structure was observed for NC 219 while NC 220 and NC 297 showed nano-web structures. All obtained NC dimensions ranged from 183 to 263 nm long and 4.70 to 4.97 nm wide. Fourier transform infrared (FTIR) spectroscopy revealed the presence of all important compositions for the cellulose of each variety, indicating that the chemical structure of DRB cellulose has not been altered by acid hydrolysis. Particle size distributions portrayed a unimodal graph for NC 220 and NC 219. This comparative study provides an insight into the possibility of using DRB as a potential source of NC. The promising characteristics of NC from MR 219 allowed its application as an emulsifier for stabilizing a solid particle-based emulsion.

Effects of two widely available and underutilized lignocellulosic materials on the mechanical and physical properties of particleboards were investigated in this work. The ratio of mixtures lignocellulosic flakes at four levels (100% aspen wood), (50% aspen wood: 25% citrus: 25% old railroad ties), (50% aspen wood: 50% citrus), and (50% aspen wood: 50% old railroad ties), and the percentage of resin in two levels (8 and 12%) were considered as variable factors. The 100% aspen wood (Populus tremula) was mixed as a control board (100% aspen wood). Then the mechanical and physical properties of the samples including modulus of rupture, modulus of elasticity, internal bond, water absorption, and thickness swelling after 2 h and 24 h of immersion (EN 310-319) and fire resistance (ISO 11925-2) were measured. The results showed that with increasing poplar wood in mixtures, modulus of rupture, modulus of elasticity, internal bond increased, while water absorption and thickness swelling decreased. Also, in comparison with the control boards, the boards that were made by mixing 50% poplar and 50% citrus branches with 12% glue had the highest mechanical strength. The results also showed that increasing the amount of old railroad ties chips in mixing caused a significant decrease in the fire retardancy of the boards.

In the milling of wood-plastic composites, the cutting temperature has a great influence on tool life and cutting quality. The effects of cutting parameters on the cutting temperatures in the cutting zone were analyzed using infrared temperature measurement technology. The results indicated that the cutting temperature increased with the increase of spindle speed and cutting depth but decreased with the increase of feed rates. In addition, based on experimental data, a BP neural network model was proposed for predicting the cutting temperatures. The value of R² was 0.97354 for the testing data, which indicates that the developed model achieved high prediction accuracy, respectively. The results of the study can play a guiding role in the prediction and control of cutting temperature, which is of great importance in the improvement of tool life, machining quality, and machining efficiency.

Lignocellulosic materials that are thermally treated via hydrolysis react chemically, modifying their internal structure, which in turn modifies their physical and mechanical properties, as well as their dimensional stability. Bamboo (Guadua angustifolia Kunth) samples 3 years old, without nodes and without skin, obtained from their basal area were subjected to thermal treatment with temperatures between 160 and 200 °C and duration times between 1 h and 4 h. The severity of the thermal treatment affects the modulus of rupture and modulus of elasticity in compression. The modulus of rupture increased at temperatures up to 180 °C with treatment times of 2 h, i.e., the severity, defined as the product of the temperature and the time varied between 320 (°C*h) and 360 (°C*h). An inflection point was obtained at a temperature of 180 °C after 2 h with a maximum value of 115.1 MPa. The modulus of elasticity increased as the temperature and time increased. The modulus of rupture and the modulus of elasticity of the treated samples increased up to 14.7% and 36.1%, respectively, compared to the not thermal treated samples. Additionally, when the density increased, the resistance and the compression stiffness also increased.

Fatty acid alkyl esters (FAMEs) derived from waste vegetable oils and non-edible oil sources are the most attractive alternative liquid biofuel in the energy field. Substitute methyl esters derived from waste cooking oil (WCO) have a lower induction period (3.12 h) and do not satisfy the Biodiesel EN 14214:2012 Standard (8 h). In this study, concentrations of 100, 250, 500, and 1000 ppm of four different types of phenolic antioxidants—butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ), and propyl gallate (PG)—were used to examine oxidative stability and improve fuel quality. PG (250 ppm) showed the most effective result of 18 h to 12.17 h of the induction period of 6 months of storage. Antioxidant effectiveness increased with regard the oxidative stability of waste cooking oil methyl ester in the following order: BHT

Electrical resistance and resistivity were measured with various types of electrodes to evaluate the moisture content of wood. The conventional two-pin method, electrically conductive fabrics, and multi-pin electrodes were used to measure the electrical resistance of Japanese larch (Larix kaempferi) wood, and a four-pin probe was used for resistivity measurements. The resistance in the longitudinal direction measured with the two-pin electrode was slightly affected by the dimensions of the wood sample, whereas the resistance measured with the conductive fabric and multi-pin electrodes was clearly affected by the end surface area in contact with the electrode and the length between electrodes. The resistivity calculated from the relationship between the electrical resistance and sample dimensions also showed differences based on the sample dimensions. The least squares regression model trained with the resistance data based on the two-pin method predicted the moisture content with a high coefficient of determination of 0.986. The four-pin probe produced the most stable resistivity regardless of the sample dimensions, making it a feasible approach for the moisture evaluation of large wood members.

The involvement of wood decay fungi and the importance of their enzymes in polyethylene degradation is well documented. Therefore, decay-resistant hardwood associated fungi should be better degraders with their versatile enzymatic systems. In the current study, decaying hardwood associated fungi were isolated and their ability to degrade low-density polyethylene (LDPE) was assessed. Thirty-three isolates were identified by sequencing the internal transcribed spacer region of nuclear ribosomal DNA. Randomly selected isolates were tested for laccase producing abilities. Three species were selected to test their potentials in LDPE sheet degradation. Fungi were incubated in Czapek-Dox broth containing 20-micron LDPE sheets at room temperature for 60 days. The biodegradation signatures were assessed by analyzing the changes in structural characteristics of LDPE using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), percent reduction of tensile properties, and weight loss. FTIR analysis revealed changes in certain functional groups compared with the control, indicating chemical changes resulting from the treatment. LDPE sheets incubated with fungi showed cracks and holes under SEM analysis, percent reduction in tensile properties, and weight loss, which are the signatures of degradation. This study revealed that the hardwood decaying basidiomycetes, Phlebiopsis flavidoalba, Schizophyllum commune, and Phanerodontia chrysosporium have the potential for in vitro LDPE degradation.