Volume 15 Issue 4

A cone calorimeter and thermogravimetric analysis were used in this work to determine the combustion and pyrolysis characteristics of decorative bamboo filaments before and after being treated with boric acid and borax (1:1) flame-retardants. The kinetics were calculated using the Coates-Redfern model. The results showed that in comparison to the control sample, the flame combustion time decreased from 52 s to 40 s, and the peak value of the heat release rate (PKHRR) and total heat release (THR) of the boric acid and borax treated samples were significantly decreased, by 21.0% and 22.2%, respectively. The peak value of the smoke release rate (PKSPR), total smoke production (TSP), and the specific extinction area (ASEA) were reduced substantially, by 90.6%, 93.3%, and 93.0%, respectively. After the boric acid and borax (1 to 1 ratio) flame retardant treatment, the pyrolysis range, the mass loss, the maximum mass loss rate, and the corresponding peak temperature of the samples all significantly decreased with the same heating rate. The activation energy of the BB-treated samples was higher than the control group, which indicated the boric acid and borax flame retardant had flame retardant efficiency.

Bagasse pulp waste (BPW) is a material generated from the depithing of sugarcane bagasse stems prior to pulping. It was subjected to a modified oxygen delignification or ammonia catalytic steam explosion (AE) pretreatment for delignification and retaining carbohydrates of raw materials, followed by simultaneous saccharification and co-fermentation (SSCF) to ethanol. Based on this process, an environmentally sustainable two-stage process for lignin purification was employed to obtain nontoxic “green lignin”. The results indicated that both pretreatment methods, particularly AE, had outstanding performance in the SSCF process. The highest ethanol yield (based on dry matter of BPW), 67.5% for the AE pretreatment, was obtained from the SSCF procedure at 8% (w/v) solids loading. Furthermore, the obtained lignin products from this process possessed better structural integrity.

Turkey holds a 95% market share of global sweet bay (Laurus nobilis L.) leaf trade, and it has 25 leaf processing and manufacturing facilities with different capacities. In this study, the usability of waste sweet bay wood (BW) that was removed from bay leaf processing plants was studied. For this purpose, three-layer particleboards were produced by mixing industrial chips (IC) and waste sweet bay wood chips (BWC) at a mixture rate of 0%, 25%, 50%, 75%, and 100%. For panel production, urea formaldehyde adhesive (UF) was used in 10% of the surface layers and in 8% of the middle layer based on dry chip weight. Some mechanical properties, such as bending strength (BS), modulus of elasticity in bending (MOE), internal bond strength (IB) of the test panels, thickness swelling (TS), and water absorption (WA) amounts, were determined. The results showed that all panel groups except group C (25% BWC + 75% IC) met the general purpose panel class (P1) requirements for use in dry conditions according to TS EN 312 (2012). In addition, group A panels (100% BWC) met the requirements of P2 class for the MOE and BS, and group E panels (75% BWC + 25% IC) met the P3 standards. The results showed that BWC could be used to produce particleboard for general purposes, including furniture.

The aim of this paper was to enhance paper strength in NaOH/thiourea aqueous solution at room temperature. Paper from cotton pulp was saturated with room temperature NaOH/thiourea aqueous solution and placed at a fixed temperature (8, 15, and 20 °C) for a period of time (1 h, 2 h, 4 h, and 6 h). The morphology, X-ray diffraction (XRD), mechanical properties, and density of paper were characterized. The results indicated the paper was self-reinforced. Scanning electron microscopy (SEM) photographs indicated that the structure of the treated papers was increasingly compact with decreasing temperature. The XRD results showed that the crystallinity degree of the paper decreased from 80.0% to 60.0%. The stress at break of the treated papers increased by more than fivefold. The wet tensile strength of the treated papers increased remarkably.

Appropriate chemical reagents were selected for removing the wax layer of bamboo culm, and optimal treatment conditions with the selected agents were determined in this study. Solutions of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium chloride, along with their mixtures with 1% sodium dodecyl sulfate, were tested for efficacy of wax removal on culms of giant timber bamboo (Phyllostachys bambusoides S. et Z.), hachiku bamboo (Phyllostachys nigra var. henosis Stapf), and moso bamboo (Phyllostachys pubescens Mazel). Of the tested reagents, the mixture of potassium hydroxide and sodium dodecyl sulfate showed the best capability. The effects of varying concentrations of the selected reagents and reaction times at 90 °C were investigated by response surface methodology (RSM). Quadratic regression models representing the degree of wax removal at various treatment conditions were determined. The coefficients of determination of the fitted models were greater than 0.98, meaning that the models were highly accurate in predicting the degree of wax removal. According to the fitted models, the optimal conditions of potassium hydroxide concentration, sodium dodecyl sulfate concentration, and reaction time were 5.08%, 3.6%, and 63 min, respectively. The use of an RSM model offers considerable flexibility for practical uses because it allows multiple solutions with any desired level of wax removal.

To meet consumer requirements for comfort in wooden structure construction, test mode methods (the environmental excitation method and impact excitation method) have been used to test six measuring points of the flooring in a two-story residential light-wood structure. The following tests were performed: the fundamental frequency test of floor structure under environmental excitation mode; the ball excitation dynamic vibration test of single and rhythmic running of a basketball and tennis ball under impact excitation mode; and the pedestrian dynamic vibration test of jump, single-step, steady walking, and rhythmic movement. The comfort analysis was validated based on the test results of peak value and effective value of fundamental frequency, acceleration, and speed. ANSYS was used to verify the calculation mode of the floor structure. Research showed that the fundamental frequencies of the building structure obtained through the calculation mode and the test mode were consistent, and both were higher than 4.5 Hz. The maximum measured acceleration peak value under the impact excitation mode was 407.2 mm/s2. The maximum speed peak value was 5.606 mm/s. The maximum acceleration effective value (RMS) was less than 450 mm/s2. The floor structure results met the building comfort requirements. The research has value in engineering applications, as it advances understanding concerning the vibration characteristics and comfort optimization of light-wood frame construction.

Fire-retardant performance was imparted to the existing wood-fiber insulation boards (WIB) via internal and external treatment with silica- and phosphorus-based fire-retardants. The combustion and smoke characteristics were investigated using a cone calorimeter. Based on combustion for 600 s, the weight loss and shrinkage of WIBs decreased due to fire-retardant treatment. The time to ignition was delayed to more than 400 s on the WIBs treated internal and external fire- retardant (WIB-IEs), whereas that of WIB with only internal treatment (WIB-I) was 5 s. The overall heat release rate (HRR), HRRpeak, and total heat release (THR) of WIB-IE specimens decreased, and the fire resistance standard Class II was satisfied. The WIB-IE2 showed higher fire resistance performance, with a HRRmean level of 6.7 kW/m2 and a THR of 1.3 MJ/m2. The WIB-I showed extremely low total smoke release (TSR) compared to the external fire-retardant treated specimen. However, the externally treated WIB-IEs had an increased TSR of 165 to 256 m2/m2 due to the increase in incomplete combustion caused by the fire-retardant. After fire-retardant treatment, CO2 generation decreased because the rate of complete combustion decreased, but CO emission increased slightly. Therefore, silica- and phosphorus-based fire-retardants by internal and external treatments were suitable for WIBs.

This paper investigated the effect of the tenon length on the strength and stiffness of the standard mortise and tenon joints, as well of the double mortise and tenon joints, that were bonded by poly(vinyl acetate) (PVAc) and polyurethane (PU) glues. The strength was analyzed by measuring applied load and by calculating ultimate bending moment and bending moment at the proportional limit. Stiffness was evaluated by measuring displacement and by calculating the ratio of applied force and displacement along the force line. The results were compared with the data obtained by the simplified static expressions and numerical calculation of the orthotropic linear-elastic model. The results indicated that increasing tenon length increased the maximal moment and proportional moment of the both investigated joints types. The analytically calculated moments were increased more than the experimental values for both joint types, and they had generally lower values than the proportional moments for the standard tenon joints, as opposed to the double tenon joints. The Von Mises stress distribution showed characteristic zones of the maximum and increased stress values. These likewise were monitored in analytical calculations. The procedures could be successfully used to achieve approximate data of properties of loaded joints.

There is increasing interest in regenerated cellulose (RC) films for advanced manufacturing applications using natural polymers and renewable materials. In this study, RC films were isolated via solution casting process using microcrystalline cellulose (MCC) and the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). Initially, MCC was synthesized from oil palm empty fruit bunch using total chlorine-free (TCF) pulping and acid hydrolysis. Effects of MCC on the structures and physicochemical properties of the isolated RC films were determined for 4 wt%, 6.5 wt%, and 9 wt% of MCC at 80 °C. Several analytical methods were employed to evaluate degree of crystallinity, chemical stability, mechanical properties, morphology, opacity, water vapor permeability, and thermal stability of the RC films. The results showed that the addition of 6.5 wt% of MCC yielded the greatest tensile strength. Compared with the RC films with 6.5 wt% of MCC, thermal stability and water vapor permeability slightly increased when the MCC content was 9 wt%. According to the analytic hierarchy process (AHP), 6.5 wt% of MCC was the optimum MCC concentration to mix with [BMIM]Cl to manufacture RC films for packaging applications, while 9 wt% of MCC was ideal for photocatalytic and electrically conductive thin film applications.

The effects of cellulose nanocrystal (CNC) particles were investigated relative to the physical, mechanical, and microstructural properties of wood cement composite panels. Wood and cement were mixed at three ratios of 1:3, 1:3.5, and 1:4. Calcium chloride was added at 3 and 5%. CNC was added to the mixture at five levels (0, 0.1, 0.2, 0.5, and 1%, based on dry weight of cement). The results showed that CNC content of 0.5% had the best impact on the properties. The overall trend showed that with the addition of CNC, tensile, flexural, and physical properties of the composites were considerably enhanced. Scanning electron microscopy demonstrated that the addition of CNC was associated with an improved integrity in the micro-structure of panels.