NC State
  • Researchpp 3299-3308Thaler, N., Lesar, B., and Humar, M. (2013). "Performance of copper-ethanolamine-impregnated Scots pine wood during exposure to terrestrial microorganisms," BioRes. 8(3), 3299-3308.AbstractArticlePDF

    Copper-ethanolamine-based wood preservatives are still the most important solutions for protecting wood in ground applications in Europe. Wood in the ground is exposed to a variety of organisms that can act synergistically. In order to simulate these conditions in the laboratory, Scots pine (Pinus sylvestris) specimens impregnated with copper-ethanolamine preservative of three different concentrations (cCu = 0.125%, 0.25%, and 0.5%) were exposed to three different soils according to procedure ENV 807, for periods between 12 and 32 weeks. After the relevant period of exposure, samples were isolated, and their mass loss, bending strength, and modulus of elasticity were determined. In the final step, the remaining copper in the samples was determined. The results showed that, in spite of significant copper leaching, the tested copper-ethanolamine-treated wood exhibited good performance in ground applications. Furthermore, a good correlation was found between the mechanical properties and mass loss, regardless of the chemical treatment applied.

  • Researchpp 3309-3321Ribeiro, G. C., Coelho, L. M., Oliveira, E., and Coelho, N. M. M. (2013). "Removal of Cu(II) from ethanol fuel using mandarin peel as biosorbent," BioRes. 8(3), 3309-3321.AbstractArticlePDF

    Mandarin peels were investigated for the removal of copper ions from ethanol fuel. Infrared spectroscopy and thermogravimetric analysis were used for elucidating possible functional groups responsible for the adsorption of Cu(II) from ethanol. The influence of parameters such as the mass of the adsorbent, sample pH, stirring time, and initial copper(II) concentration was investigated using multivariate optimization strategies. The optimum conditions were a pH value of 7.0, a stirring time of 10.0 min, an initial copper(II) concentration of 6.0 mg L-1, and an adsorbent mass of 95.0 mg. The sorption data were fitted satisfactorily to the Langmuir and Freundlich isotherm models. The mandarin peel presented a maximum adsorption capacity of 2.71 mg g-1 and is low-cost, which makes it suitable for the removal of copper ions from ethanol fuel.

  • Researchpp 3322-3335Sabo, R., Jin, L., Stark, N., and Ibach, R. E. (2013). "Effect of environmental conditions on the mechanical properties and fungal degradation of polycaprolactone/microcrystalline cellulose/wood flour composites," BioRes. 8(3), 3322-3335.AbstractArticlePDF

    Polycaprolactone (PCL) filled with microcrystalline cellulose (MCC), wood flour (WF), or both were characterized before and after exposure to various environmental conditions for 60 days. PCL/WF composites had the greatest tensile strength and modulus compared to neat PCL or PCL composites containing MCC. Electron microscopy indicated better adhesion between WF particles and PCL than between MCC particles and PCL. Neither wood flour nor MCC cellulose appeared to significantly affect the crystallinity of PCL. Environmental conditioning resulted in only minor deterioration of mechanical properties, although samples soaked in water had greater deterioration of mechanical properties than those in high humidity or freezing environments. After a modified 12-week soil block test, specimens made with wood flour lost weight and showed signs of decay after exposure to the brown-rot fungus Gloeophyllum trabeum.

  • Researchpp 3336-3346Yao, J., Lu, W., Rong, S., and Hu, Y. (2013). "Mechanical properties evaluation of coir toughened unsaturated polyester with different reinforced body forms," BioRes. 8(3), 3336-3346.AbstractArticlePDF

    Unsaturated polyester (UPE) composites reinforced with natural fiber as non-structural materials have been used in engineering.In this study, three different types of coir-reinforced UPE consisting of coir non-woven needle mat (CNM), coir mesh (CM), and coir rope (CR) were produced , and the mechanical properties, such as flexural strength (FS), tensile strength (TS), and impact toughness (IT), were investigated. With the exception of FS, CR-reinforced UPE composites exhibited better mechanical properties, mainly due to good directionality of the coir fibers. Dynamic mechanical analysis (DMA) was also carried out to analyze the composite performances under wide temperature ranges. All the tests confirmed the beneficial effect of coir on the UPE matrix, noting that composites with higher toughness perform better in most applications.

  • Researchpp 3347-3357Xu, M., Xu, M., Dai, H., Wang, S., and Wu, W. (2013). "The impact of synthesis conditions on the structure and properties of di-(stearylamidoethyl) epoxypropyl ammonium chloride," BioRes. 8(3), 3347-3357.AbstractArticlePDF

    Both alkylketene dimer (AKD) and alkenyl succinic anhydride (ASA) are widely used neutral papermaking sizing agents. However, AKD has the issue of sizing hysteresis, while ASA requires on-site emulsification. In addition, both reagents are readily hydrolyzed. Di-(stearylamidoethyl) epoxypropyl ammonium chloride (DSEAC) has been applied as a fabric softener, but it is a potential sizing agent which leads to good sizing without sizing hysteresis. It could be synthesized by a two-step process starting from stearic acid and diethylenetriamine. During the process, the stearamide structure obtained from the first step plays a key role in the second process as well as sizing. This paper focuses on the impact of the synthetic process of the first step on the structure and sizing properties of DSEAC. Single factor experimental results demonstrated that the optimal temperature should be 160 °C while the optimal reaction time should be less than 3.5 hours. Orthogonal analysis experiments indicated that the optimal synthetic process was maintaining 100 °C for 30 min, and then increasing the temperature to 160 °C for 3.5 hours. Dosages of the catalysis and antioxidant were 0.5% and 0.6% of stearic acid, respectively.

  • Researchpp 3358-3371Lamaming, J., Sulaiman, O., Sugimoto, T., Hashim, R., Said, N., and Sato, M. (2013). "Influence of chemical components of oil palm on properties of binderless particleboard," BioRes. 8(3), 3358-3371.AbstractArticlePDF

    The influence of chemical components of oil palm on properties of binderless particleboard were evaluated through a series of mechanical, physical, and chemical analyses in order to assess the self-bonding mechanism. Binderless particleboards were evaluated by relating the physical and mechanical properties to the chemical components. Results revealed that the addition of glucose and sucrose onto the board with and without extraction increased the modulus of rupture and internal bond strength. Glucose and sucrose also reduced the thickness swelling and water absorption of the board. The addition of starch onto the board enhanced the strength of the board, though sugar addition enhanced the board strength more than starch. Adding the sugar also lowered the xylose/ arabinose ratio, indicating that the boards consist of short-chain polymers with a large amount of branching with other monosaccharides. This implies that sugar content present in oil palm trunk plays a major role in the bonding of binderless boards.

  • Researchpp 3372-3384Gašparík, M., and Gaff, M. (2013). "Changes in temperature and moisture content in beech wood plasticized by microwave heating," BioRes. 8(3), 3372-3384.AbstractArticlePDF

    This paper reports on changes in temperature and moisture content after plasticizing beech wood by microwave heating. There is currently no known use of microwave heating for plasticizing wood. Therefore, a proper procedure was developed to verify the use of microwave heating for the purpose of plasticizing. Moisture content was monitored in beech test samples with dimensions of 25 × 25 × 400 mm and 40 × 40 × 600 mm, while temperature was investigated only on samples 25 × 25 × 400 mm. In all cases, the temperature was suitable for the wood bending process. Microwave heating is quite intense, therefore for this kind of heating, it is better to have higher moisture content in the appropriate power device and minimal plasticizing time. The biggest advantage of microwave heating is the short plasticizing time, a few minutes, while steaming requires tens of minutes or even hours.

  • Researchpp 3385-3398Pelletier, A., Zhao, Y., Lei, X., and Li, K. (2013). "Improved fiber separation and energy reduction in thermomechanical pulp refining using enzyme-pretreated wood," BioRes. 8(3), 3385-3398.AbstractArticlePDF

    Black spruce (Picea mariana) wood chips were subjected to enzymatic pretreatments, using an enzyme formulation containing cellulolytic and hemicellulolytic enzymes, combined with light mechanical treatments including downsizing and/or compression/decompression. These pretreatments were followed by 3 stages of mechanical refining in a lab-scale disc refiner. Depending on the treatment, the overall energy savings obtained could be as high as 15%. Most of the savings were obtained during the first stage of refining. Pulps collected after this stage were imaged using TEM and SEM. Differences were observed between differing treatment types. The most significant differences were seen when macerated chips were compressed and allowed to decompress in enzyme solutions. Enzyme treatments are able to change the rupture pattern during refining, thus lowering the overall specific energy consumption (SEC) as evidenced by improved pulp freeness and direct energy measurements. Increasing enzyme penetration helps to improve the overall SEC savings and also improves the distribution of energy savings throughout the refining stages by moving initial fiber separation from the middle lamella into the secondary wall.

  • Researchpp 3399-3413Hamaguchi, M., Saari, J., and Vakkilainen, E. (2013). "Bio-oil and biochar as additional revenue streams in South American kraft pulp mills," BioRes. 8(3), 3399-3413.AbstractArticlePDF

    Pulp and paper companies are seeking opportunities beyond the traditional production of market pulp. One interesting alternative is to expand their revenue streams by adding value to the wood residues that they generate. Considering that excess heat and electricity can be used for biomass pre-treatment and conversion, the aim of this work is to show how the integrated production of bio-oil or biochar would affect the operation of a 1.5M t/a kraft pulp mill in South America. Detailed balances with a focus on modern eucalyptus mills are then developed for this purpose. Since the attractiveness of increasing renewable energy is often influenced by energy policies or local market development for the new products, the target was not to determine the best investment decision. Nevertheless, an economic analysis was performed to observe the main variables affecting the viability of these technologies. The results showed that satisfactory internal rates of return can be achieved for multiple technologies depending on the price of electricity, torrefied pellets, or bio-oil.

  • Researchpp 3414-3425Wang, L., and Li, J. (2013). "Electromagnetic-shielding, wood-based material created using a novel electroless copper plating process," BioRes. 8(3), 3414-3425.AbstractArticlePDF

    A copper coating was deposited on Fraxinus mandshurica veneers to create an EMI-shielding, wood-based material via a simple electroless copper plating process. The wood veneers were pretreated in a NaBH4 solution. The wood veneers treated with NaBH4 were immersed in a plating bath in which copper coating was successfully initiated. The coatings were characterized by SEM-EDS, XPS, and XRD. The metal deposition, surface resistivity, and the effectiveness of electromagnetic shielding were measured. The morphology of the coating was uniform, compact, and continuous. The grain of the wood was preserved on the plated wood veneer, which had a copper-like color. But the samples were less glossy compared to those from Pd activation. EDS, XPS, and XRD results indicated that the coating consisted of Cu0 with a crystalline structure. The surface resistivity and copper deposition were 0.399 Ω/cm2 and 31.98 g/m2 when the veneer was pretreated with a 3 g/L NaBH4 solution for 10 min and plated for 25 min at 60 °C. The plated veneers exhibited good electromagnetic shielding effectiveness of over 40 dB in frequencies ranging from 10 MHz to 1.5 GHz.