Volume 10 Issue 3

Bio-oil can be fractionated into three parts according to their boiling points. This research reported that light distillates could be converted into oxygenated liquid fuels through a two-stage hydrotreatment approach, using a Pd/C catalyst. The main goal of the first hydrotreatment stage was to stabilize the high active components, which contained carbon–carbon double bonds and aldehyde groups. The second hydrotreatment stage aimed to saturate the components with benzene rings and keto groups, resulting in saturated oxygenated compounds. The H/Ceff ratio was improved greatly after the two-stage hydrotreatment, increasing from 0.51 (in the reactant) to 1.67 (in the final products). The high heating value of the final products was 31.63 MJ/kg. After the two-stage hydrotreatment, the main products were C5–C9 alcohols, which were tested via gas chromatography–mass spectrometry. The products could be blended with gasoline directly. Based on the experiments regarding the hydrogenated model compounds, a reaction schematic for the two-stage hydrotreatment was created. Moreover, the bio-oil hydrotreatment kinetics were investigated. The order of the hydrotreatment reaction was 2.0, and the apparent activation energy (Ea) was 57.29 KJ/mol.

There are different dynamic or static test methodologies for evaluating the shear and torsional moduli of wood. A preferred method is nondestructive, accurate, and standard. However, dynamic methods using conventional devices previously suggested for determining the orthotropic shear moduli of wood are neither accurate nor standard. Thus, a reliable method for evaluating the torsional modulus of wood through a torsional vibration test exists; however, it is not a standard test method at all. In this study, a standard methodology for refractory materials, ASTM C1548, was fitted to wood to meet the qualifications suggested in measuring the torsional vibration of an orthotropic material. A methodology based on Timoshenko’s advanced theory of free flexural vibration for orthotropic shear moduli was also defined to be compared to these reliable, standard procedures of torsional modulus evaluation. A promising conclusion was derived using improved computer-based instrumentation.

Conductive papers were prepared via surface coating with graphite or carbon black using either carboxylated styrene butadiene latex or starch as the binder. It is of practical interest to determine the percolation threshold for the coated paper product made using a binary system consisting of conductive filler and binder. In this study, the electro-conductivity threshold of various conductive papers was determined based on experimental data according to the percolation law. Results showed that the conductivity of coated, conductive paper is a function of the volume fraction of conductive filler, which can be described well by the percolation theory. The percolation thresholds of graphite/latex, graphite/starch, carbon black/latex, and carbon black/starch coatings were 17.66, 12.36, 11.71, and 8.69 vol.%, respectively. At concentrations higher than the percolation threshold, the conductivity of conductive paper using graphite as the conductive filler was much higher than that achieved using carbon black at a similar volume fraction. The present paper has significant practical implications for conductive paper technology using graphite filler based on surface coating technology.

The filamentous fungus Aspergillus terreus was cultivated in a 2-L stirred tank bioreactor, and the resulting culture filtrate was used for protein purification. From the cultivation broth, seven crude extracts of glucanase and one of β-glucosidase were purified. A total of eight components were identified, including endoglucanases (Endo I, II, III, and IV), cellobiohydrolases (CBH I, II, and III), and β-glucosidase. The eight major components in the fermentation broth of A. terreus, which most likely constitute the essential enzymes for cellulose hydrolysis, were further purified by a series of column chromatography steps. Interestingly, the β-glucosidase from A. terreus displayed an extremely high activity on p-nitrophenyl-β-D-glucopyranoside (pNPG), which suggests that it is a good candidate enzyme for the conversion of cellobiose to glucose. The temperature and pH ranges for optimal activity of the purified enzyme were 46 to 62 °C and 5.0 to 6.0, respectively.

The thermal degradation behavior and pyrolysis kinetic models of wood flour (WF)/PVC composites before and after adding chitosan were studied using thermogravimetry (TGA) and nine common kinetic model functions (f(α)). The results indicated that the thermal degradation temperature of WF/PVC composites was delayed to a higher value after adding chitosan. The first-order reaction order (L1) model and second-order reaction order (L2) model were found to be the best reaction order functions for the description of mass loss kinetics of WF/PVC without chitosan during the first and second stages. Two L2 models were suitable for both degradation stages of WF/CS/PVC. Activation energy (E) and frequency factor (A) for WF/PVC and WF/CS/PVC corresponded to 26.05 kJ·mol-1, 4.08×103 s-1, and 40.89 kJ·mol-1, 2.11×1010 s-1 at the first degradation stage, respectively, and 97.83 kJ·mol-1, 1.11×107 s-1 and 92.88 kJ·mol-1, 1.56×1011 s-1 at the second degradation stage.

Wood-plastic composites (WPC) have been developed into new and important wood-based composites because of their benefits for the environment, economy, and recyclability. When combined with structural adhesives, WPCs will have a greatly broadened application in the construction field. In this work, epoxy resin and acrylic ester were used to bond WPC adhesive joints. The shear strength of the adhesive joints was determined and investigated. Resonant frequency and dynamic modulus of elasticity (MOE) of the WPC adhesive joints were measured using the longitudinal vibration method. The correlation between different vibration parameters and shear strength of WPC adhesive joints was also investigated. Results showed that the epoxy resin had a better bonding quality than the acrylic ester on the bonding of WPC adhesive joints. The resonant frequency, dynamic MOE, and the dynamic MOE ratio of the WPC adhesive joints had close correlations with their shear strength for the samples bonded with epoxy resin.

Characterization of the dissolved and colloidal substances (DCS) in the process water of a bleached chemithermomechanical pulp (BCTMP) production line showed that the major lipophilic substances (wood resins) were dehydroabietic acid, linoleic acid, oleic acid, and palmitic acid. Model compound experiments indicated that polysaccharides contained in DCS had significant effects on the stability of the system. Effects of neutral and acidic polysaccharides on the stability of wood resins (model resin acid R and fatty acid O) in the presence of metal ions were then investigated. No calcium-induced aggregation occurred when the concentration ratio of added neutral polysaccharide to R and O exceeded 0.2 and 1.0, respectively. Acidic polysaccharide could further degrade the stability of resin dispersions in the presence of calcium ions and yet have a positive effect in the presence of only sodium ions.

In this paper, the depolymerization of lignin was successfully achieved by the thermal treatment of kraft lignin in butyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride ([DBUC4+][Cl-]) without a catalyst. The thermal treatment experiments were performed in an oven at 150, 200, and 250 °C for 1 h. The changes in kraft lignin structure over the course of depolymerization were characterized by gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and 1H / 31P NMR analyses. GPC chromatograms indicated that the retention time of the original kraft lignin had shifted toward higher values after the thermal treatment, which indicated lignin depolymerization. The average molecular weight of the lignin obtained after 1 h reaction time decreased by 23, 70, and 58 wt% for the treatment at 150, 200, and 250 °C, respectively. FTIR spectra indicated the cleavage of β-O-4 bonds of kraft lignin. The 1H NMR spectra showed demethylation of all treated kraft lignins. Moreover, the 31P NMR analysis demonstrated that the demethylation phenomenon of the treated kraft lignin contributed to the formation of catechol groups.

Time-domain reflectometry (TDR) can be used to predict the moisture content in porous materials, including soil, and is an exciting tool that could be used to measure the moisture content in wet-stored wood. Three-rod probes with 127 mm- or 152 mm-long rods were inserted into 62 loblolly pine and 34 sweetgum saturated bolts. The bolts were air dried over a span of five weeks. TDR waveforms and moisture content were periodically recorded. In total, 534 and 482 readings were taken for the loblolly pine and sweetgum bolts, respectively. An algorithm in R was written to automatically analyze the apparent length of the TDR rods. Calibration models were developed between moisture content and X (apparent length / actual rod length). A three-parameter logistic model was developed for loblolly pine (R2=0.64) and sweetgum (R2=0.84). The process was repeated using shorter bolts and 152 mm-long rods, resulting in improved models for loblolly pine (R2=0.99) and sweetgum (R2=0.97). Overall, TDR and the algorithm written to analyze the waveforms were accurate in predicting moisture content and could be used to monitor moisture in wet-decks.

A simple method was invented to achieve a high yield of cellulosic biomass-derived alkyl levulinates, which have the potential to be alternative fuel additives. Alkyl levulinates, such as butyl-, pentyl-, and hexyl levulinates, were produced using single-step acid-catalyzed solvolysis of cellulosic biomass without the use of elevated pressure. Reactions were performed by refluxing alcohols such as 1-butanol, 1-pentanol, and 1-hexanol at their boiling points of 117, 138, and 157 °C, respectively, with sulfuric acid at ambient pressure. After 1 hour of the reaction, the cellulosic biomass was converted into an alcohol-soluble compound, and a high yield of alkyl levulinates was achieved. Although the process involved simple treatment under atmospheric pressure, the alkyl levulinate yield was quite high: 60 to 80% based on the hexose content of the cellulosic biomass. The factors influencing the reaction, such as the accessibility to cellulose and acidity of the reaction media, could be controlled appropriately in this solvolysis system.