Volume 9 Issue 4

The effects of polyethylene grafted maleic anhydride (PE-g-MA) on the properties of poly (vinyl chloride)/epoxidized natural rubber (PVC/ENR) kenaf core powder composites were studied, with four different loadings of kenaf core powder (5, 10, 15, and 20 phr). The tensile properties indicated that the strength and elongation at break of the composites exhibited an increase for samples with PE-g-MA. Morphological analysis using a scanning electron microscope (SEM) showed better dispersion of kenaf fiber with the addition of PE-g-MA and less kenaf powder agglomeration. Furthermore, the swelling index indicated that composites with PE-g-MA showed lower toluene absorption than composites without PE-g-MA.

Experiments were performed to test the compressive strength of bamboo scrimber board at different grain angle directions. Investigation of test samples allows for the identification of the correlation between compression failure stress and various failure mechanisms at different grain angles. The results of the experiments showed that the density of bamboo scrimber influenced compression failure stress linearly. A new approach to describe the failure stresses of bamboo scrimber was proposed. The density was introduced as a model parameter to describe compressive properties at varying angles of grain. In comparison to a one-dimensional model, there was much less relative error between predicted values and measured values by this 2D model. This report aims to improve the precision of existing strength models for various grain angles and to provide a competing method for the practical use of bamboo scrimber.

We examine U.S. exports and imports of hardwood products from 1990 to 2013. These products include logs, lumber, veneer, chips, molding, cooperage, plywood, and flooring. The values of hardwood products exported and imported have fluctuated over the years but have generally increased. More substantial changes have occurred with the countries and regions receiving U.S. exports, as well as with those importing into the United States. The primary region receiving U.S. hardwood log and lumber in 1990 was Western Europe, but today, China is the most important market. East Asia has been the most important source region for U.S. hardwood plywood imports, but the specific sources have shifted from Indonesia and Taiwan in 1990 to China today. The overall balance of U.S. hardwood product trade has remained positive for most of the years examined, with the United States having a comparative advantage in exporting logs and lumber. In contrast, the United States has a comparative disadvantage in hardwood plywood exports.

This research analysed the colour properties of new Robinia varieties with enhanced growing rates. The investigations comprised new Robinia varieties grown on different East Hungarian sites. The colour coordinates were determined in the international CIELab system. The mean colour values of the wood of the different varieties did not show significant differences. However, the standard deviation of the measured colour coordinates showed higher values in the case of almost all varieties with high growth rates, compared to the controls (non-fast-growing). The higher colour variegation of most of the fast-growing varieties is attributed to some genetic property, as the standard deviation is independent from the mean annual ring width and the production site.

Corn stover was successfully liquefied by microwave heating at 160 °C with ethylene glycol (EG) used as the solvent and sulfuric acid as a catalyst. Gas chromatography and mass spectrometry (GC-MS) data indicated that methyl esters, including 3-(2-methyl-1,3-doxolane-2-yl) propionic acid methyl ester (PAME), levulinic acid isopropyl ester (LAE), methyl laurate, and methyl palmitate were the major degradation compounds, in addition to EG derivatives in the liquefied product of corn stover (LPCS). For high value-added utilization of LPCS, solvent extraction was applied to characterize the components and to separate it into useful fractions. After being dispersed in water, the water-soluble fraction of the LPCS was then extracted with organic solvents, including hexane, chloroform, diethyl ether, and ethyl acetate. Levulinic acid isopropyl ester showed the highest distribution in chloroform and ethyl acetate, while the lowest in hexane and ether. Levulinic acid isopropyl ester was selectively enriched to 28.76% and 43.65% by sequential extraction with chloroform and ethyl acetate, respectively, in accordance with the quantitative analysis.

The wettability of a solid material is very important in many applications, such as food, agrochemical formulations, and cosmetics. Wettability can be improved by adding surface active agents, especially biocompatible surfactants derived from biomass. In this work, the surface activity (ability to lower the surface tension of an aqueous solution) and wettability toward a hydrophobic powder by a series of sodium lignosulfonates (NaLS) synthesized with different degree of sulfonation (QS) and weight-average molecular weights (Mw) were investigated by measuring the surface tension and contact angle. The results demonstrated NaLS with a larger Mw or lower QS had higher surface activity. Conversely, the wettability of the NaLS aqueous solution toward difenoconazole powder showed a reverse trend, i.e., NaLS with a smaller Mw or higher Qs improved the wettability to difenoconazole. The surface activity and wettability was controlled by the varying densities of the NaLS molecules at the water to air interface or the solid/liquid interface, which was dependent on the molecular structure of NaLS.

This manuscript describes the analysis of xylanase production by Aspergillus niger NRRL 328 in solid state fermentation (SSF) of soybean husks. A maximum value of extracellular xylanase activity of approximately 950 U g-1 was achieved after 96 h. Proteomic analyses performed on the enzymatic mixture responsible for the maximum value of xylanase activity in SSF revealed the presence of two xylanases. This xylanolytic mixture was partially purified and characterized. It followed Michaelis-Menten kinetics towards xylan, with a KM of 7.92 ±0.97 mg xylan/mL and a Vmax of 262.2 ± 27.8 g L-1 s-1. The optimum pH for the enzyme is 5.3, and the optimal temperature is 50 °C. The enzyme retains 100% of its activity at 40 °C for at least 1 month. It shows very high stability in a broad pH range, with a half-life of 40 days at pH 5.3, pH 6.0, pH 6.5, pH 7.0, and pH 8.0.

The focus of this work was to determine the 3D moldability of veneers on circular test pieces treated with steam plastification. These results were compared with results acquired from pieces laminated with three different types of laminating foils with thicknesses of 80, 100, and 125 µm before proper 3D molding. The purpose of test piece lamination was to change the degree of pre-stress and move the neutral plane into the laminating foil, which actually works as a flange. Results acquired from sets of test pieces modified by steam plastification and lamination were compared with the results acquired for the set of test pieces without any treatment. To determine the effects of wood type, the results obtained with beech wood of 0.5-mm thickness were compared with the results acquired from birch wood of 0.5-mm thickness using two types of spherical stamping tools with 20-mm and 40-mm diameters for molding the test pieces. The final examined characteristics were the means of attachment of the test pieces; i.e., the effect of loose attachment and attachment with a hold. The characteristic of maximum deflections was examined during 3D-molding. To measure the listed results, a testing appliance was specially designed and constructed.

The flexural properties, mass losses, and moisture behavior of thermally modified Douglas-fir pretreated with boron or glycerol were examined. Pretreatments were associated with slight, but not significant, reductions in modulus of rupture (MOR) and modulus of elasticity (MOE) of Douglas-fir at different thermal treatment levels. Boron pretreatment had the greatest effect on MOR. MOR of non-pretreated and boron-treated samples increased slightly at the initial stage of thermal treatment and then decreased with rising temperature and time. The MOR of glycerol-treated samples decreased with increasing temperature and time. The thermal treatments employed had no significant effect on MOE. Both temperature and pretreatments improved anti-swell efficiency. Further studies are underway to characterize the nature of the chemical changes associated with the thermal modification process.

The structural evolution of Panicum virgatum lignin during hydrothermal depolymerization was investigated. Product distribution from various temperatures was studied using gas chromatography-mass spectrometry (GC-MS ) and gel permeation chromatography (GPC) analysis. The physical-chemical properties of initial lignin, tetrahydrofuran soluble fraction, and char were also comparatively characterized by elemental analysis, scanning electron microscopy (SEM), thermogravimetry (TG), and Fourier transform infrared (FT-IR) spectroscopy. Results showed that both the depolymerization and repolymerization were significantly temperature-dependent. The undesired char formation becomes obvious when the temperature is greater than 180 °C. Further investigation demonstrated that H lignin is the most accessible for hydrothermal depolymerization, whereas S lignin is the most recalcitrant. Moreover, under the thermal effect and the dissolution of the subcritical water, the basic structure of lignin was first collapsed and then further decomposed into low-molecular weight products by the fracture of ether bonds, accompanied by char formation after repolymerization and dehydration.