Volume 9 Issue 1

Oil heat treatment can effectively improve the dimensional stability and bio-durability of wood. However, the characteristics of high oil uptake (50 percent or higher) and high susceptibility to leaching from wood have an adverse effect on subsequent manufacturing processes of wood product and production costs. A solvent extraction (100% ethanol) process was used to extract the surplus oil from the treated wood. Because the making of powder specimens from high oil uptake wood would result in experimental error, a new method of determination of oil uptake percentage was proposed by two step Soxhlet extraction with ethanol. The oil uptake percentage of oil-heat-treated poplar wood at 180 °C for 2 h with this method was determined to be 113.29%. Additionally, the average oil uptake percentage (OUP) of oil-treated poplar after the oil extraction process for 2 and 6 h was 54.82% and 29.11%, respectively. Moreover, the average oil extraction percentage (OEP) of specimens with the oil extraction process at the first step (wood sticks) in the Soxhlet extractor apparatus was larger than that of oil-heat-treated poplar specimens. Due to the combined effect of chemical changes in the wood at high temperatures and of oil uptake by the wood, the compression strength parallel to the grain changed at different OUP levels.

Industrial hemp is a non-wood fiber material that can be used for papermaking due to a high yield of hemp raw material and high-quality physical properties of its pulp. Hemp is already used as a raw materialfor papermaking and other industrial productions. The chemical composition of hemp root bast (HRB) was analyzed. HRBs were pulped using a soda-anthraquinone (Soda-AQ) process and bleached with oxygen (O), chlorine dioxide (D), and alkali (E) using the bleaching sequence OD0ED1. The results showed that HRB can be a suitable raw material for papermaking; the HRB pulp had a high viscosity (893 mL g^-1) and brightness (85.52% ISO-brightness).

Causticizing calcium carbonate (CCC), known as lime mud, is a by-product of the papermaking industry that comes from the green liquor causticizing process. In China, CCC has been used as a paper filler to replace precipitated calcium carbonate (PCC). This is beneficial for saving resources and preventing secondary pollution. Unfortunately, compared with PCC, CCC can reduce the sizing efficiency of alkyl ketene dimer (AKD). So the application scope and dosage of CCC has been limited in mill trials in China. In this study, CCC was prepared with green liquor and quicklime, which were obtained from an alkali recovery line of a pulping mill. The reason for the lower sizing efficiency of AKD when CCC was used as a filler was investigated. The results showed that when greater amounts of AKD were adsorbed by CCC, the AKD sizing efficiency was lower. The irregular CCC had higher (BET ) surface area and Barrett-Joyner-Halenda (BJH) method cumulative desorption pore volume, resulting in higher adsorption. The spindle-like or needle-like CCC had lower BET surface area and BJH method cumulative desorption pore volume that was beneficial for controlling its adsorption of AKD and improving the sizing efficiency.

Magnesium-based alkali is an attractive alkaline source for the peroxide bleaching of high-yield pulp. However, little information is available on Mg(OH)2 application in the final peroxide bleaching stage of wheat straw pulp. The use of Mg(OH)2 was demonstrated as a partial replacement for NaOH in the peroxide bleaching of a chelated oxygen-delignified wheat straw pulp. The yield, viscosity, and strength properties of bleached pulp significantly increased with increasing replacement ratio of Mg(OH)2, while the chemical oxygen demand load (COD) of filtrate was decreased. s were higher, by 2.1 Nm.g-1 and 1.75 mN*m2.g-1, respectively, than that of control pulp bleached with NaOH as the sole alkaline source. When the MgSO4 was eliminated and the dosage of Na2SiO3 was decreased in the bleaching process, the tear and burst indices of the bleached pulp were also enhanced, with the brightness maintained. Scanning electron microscopy (SEM) showed that more swelling occurred in the fibers of bleached pulp from the Mg(OH)2-based bleaching process. Fiber analysis indicated that peroxide bleaching with Mg(OH)2 increased the proportion of fiber lengths between 0.20 to 1.20 mm and 1.20 to 7.60 mm.

Two new tree variants, namely Acacia hybrid and second-generation Acacia mangium, have been introduced in plantation forests in Sarawak, Malaysia, and their wood qualities were examined. The mean basic density of Acacia hybrid was comparable with Acacia mangium. However basic density and strength properties of second-generation A. mangium were significantly lower compared to Acacia hybrid. The mean fibre length and fibre wall thickness in the hybrid were found to be greater than that of second-generation A. mangium. Fibre diameter and fibre lumen diameter of Acacia hybrid were smaller compared to second-generation A. mangium. Runkel and slenderness ratios of Acacia hybrid and second-generation A. mangium fibres showed that they were suitable for pulp and paper production. Acacia hybrid was more resistant to Coptotermes curvignathus attack than second-generation A. mangium. A laboratory soil block test showed that Acacia hybrid and second-generation A. mangium were moderately durable timbers. In summary, marked differences in wood properties and qualities were observed between Acacia hybrid and second-generation A. mangium.

Pyrolysis of olive oil industry wastes was carried out using stepwise isothermal fast pyrolysis (SIFP). SIFP consists of a succession of isothermal fast pyrolysis reactions in which the solid products obtained from the previous isothermal fast pyrolysis reaction become the substrates for subsequent reactions at higher temperatures. This article reports the results obtained from the SIFP of olive oil residue carried out between the temperatures of 300 and 500 °C using 100 °C intervals under reduced pressure (200 mm Hg). The maximum yield of liquid products occurred at 300 °C and consisted of around 35% bio-oil, which contained mainly phenols, furans, and fatty acid methyl esters (FAME). At 400 and 500 °C, FAME, which is derived from residual olive oil, was the major product.

To reveal the structural changes of lignin during the soda–AQ cooking process and chemical bonds between lignin and xylan of wheat straw, 13C isotope-labeled technology was used in this study. First, 13C isotope-labeled xylose was injected into the living wheat straw. The success of 13C isotope-labeling was confirmed by the results of 13C abundance determination. Then, milled wood lignin-13C was extracted from wheat straw. The wheat straw, which had already been labeled by xylose-13C, was cooked by the soda-AQ process. Soda-AQ Lignin-13C and Residual Lignin-13C were extracted from black liquor and residual pulp. FT-IR, 13C-NMR, and 2D HSQC NMR analyses indicated that all lignin preparations were HGS-type lignin. The main lignin linkages were β-O-4’ units, β–β’ units, β-5’ units, and β-1 units, with the highest content of β-O-4’. Furthermore, 82.8% of β-O-4’ units, 77.2% of β–β’ units, 75.4% of β-5’ units, and 75.4% of β-1 units were degraded during the cooking process. LC bonds between lignin and xylan were at C2 and C5 positions of xylan. It was found that the C-2 position of xylan in wheat straw could be mainly connected to lignin by γ-ester bonds, and C-5 position of xylan in wheat straw was possibly linked with lignin by benzyl ether bonds.

The effects of densification temperature, planing, circular sawing, and sanding on the surface roughness of densified Scots pine using the open-system thermodynamic method were studied. Densification was applied to Scots pine at 6 MPa pressure and at temperatures of 120 °C, 140 °C, and 160 °C. A total of 1040 specimens (160 × 50 × 10 mm) were prepared using the surfacing techniques of planing, circular sawing, and sanding. The surface roughness of the specimens were measured in conformance with the TS 2495, EN ISO 3274, and the TS 6212 EN ISO 4288 standards, and the results were subjected to statistical analysis. The surface roughness of the planed surfaces was 26% lower, of the surfaces cut circularly was 38% lower, and of the sanded surfaces was 32% lower in densified Scots pine compared to undensified Scots pine. According to the densification temperature, while the lowest roughness was obtained in the densified specimens at 140 °C, raising the temperature to 160 °C increased the roughness. An increase in the number of blades in planing, the tooth number in circular sawing, and the grit number in planing decreased the surface roughness. Furthermore, the roughness was less in tangential surfaces compared to radial surfaces.

Cellulose nanocrystals (CNCs), also called cellulose nanowhiskers, cellulose nanorods, or nanocrystalline cellulose, were prepared from Phyllostachys heterocycla using a commercial cellulase for hydrolysis. The enzymatic hydrolysis process and application performance as well as the biocompatibility of the CNCs were investigated. Here, the cellulase hydrolysis conditions were optimized at a cellulase dosage of 0.01 mL/g dried fibers, a hydrolysis temperature of 60 °C, a hydrolysis time of 3 h, and a bamboo fiber concentration of 2 wt%. Under these conditions, the resultant CNCs retained more similarities to the original bamboo fibers than those fabricated by sulfuric acid hydrolysis. The product also demonstrated potential biocompatibility, which expands its applicability in the biopharmaceutical and biomedical fields.

Thermal stability behaviour of coconut coir, banana pseudo stem, pineapple leaf, and sugarcane bagasse fibres was investigated under nitrogen atmosphere. The parameters of degradation kinetics were determined by thermogravimetric analysis at heating rates of 5, 10, 15, 20, 30, and 40 °C/min using the Kissinger, Flynn-Wall-Ozawa and Friedman model-free methods. Thermal degradation of these fibres showed both two and three mass loss steps attributed from the moisture evaporation and to the decomposition of cellulose, hemicelluloses, and lignin as well as other organic materials. The results also showed that activation energy was an increasing function of conversion (α), and an apparent activation energy of 75 to 200 kJ/mol was found for most of the fibres throughout the polymer processing temperature range. These findings are significant for developing a fundamental approach to understand the thermal decomposition behaviour of agricultural waste fibres in the course of biocomposite and bio-ethanol production.