NC State
BioResources
  • Researchpp 464-476Zhang, Y., Gu, J., Tan, H., Di, M., Zhu, L, and Weng, X. (2011). "Straw based particleboard bonded with composite adhesives," BioRes. 6(1), 464-476.AbstractArticlePDF

    Environmentally friendly particleboard was prepared with wheat straw, an inexpensive material. The particleboard was produced by a mixing process, using a composite adhesive comprised of urea-formaldehyde (UF) adhesives and EPU. The performance of the board was evaluated by measuring internal bonding strength (IB), thickness swelling, modulus of rupture (MOR), modulus of elasticity (MOE), and formaldehyde emission. The experimental results showed that maximum of dry and wet internal bonding strength, modulus of rupture, modulus of elasticity were 0.45MPa, 0.18MPa, 31.80MPa, and 5043MPa, respectively. The thickness swelling (TS2h) and thickness swelling (TS24h) were 3.9% and 10.7%, respectively. The composite adhesives and particleboards were measured by differential scanning calorimentry (DSC), dynamic mechanical analyzer (DMA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) measurements. The results indicated that the composite adhesive of UF/EPU could contribute to excellent mechanical, thermal, and water-resistant properties of the wheat straw particleboards.

  • Researchpp 477-486García-Ortuño, T., Andréu-Rodríguez, J., Ferrández-García, M. T., Ferrández-Villena, M.., and Ferrández-García, C. E. (2011). "Evaluation of the physical and mechanical properties of particleboard made from giant reed (Arundo donax L.)," BioRes. 6(1), 477-486.AbstractArticlePDF

    Single-layer experimental particleboards were made from various sizes of Arundo donax particles bonded with urea formaldehyde resin. The experimental panels were tested for their mechanical strength including modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), screw holding strength (SH), and physical properties (density, moisture content, thickness swelling (TS), and water absorption (WA)) according to the procedures defined by European Union (EN) Standards. The overall results showed that most panels exceeded the EN Standards for MOE, MOR, and IB. The mechanical properties of the particleboard were enhanced as the density increased. Particle size was found to have a profound effect on the board properties.

  • Researchpp 487-512Frone, A. N., Panaitescu, D. M., Donescu, D., Spataru, C. I., Radovici, C., Trusca, R., and Somoghi, R. (2011). "Preparation and characterisization of PVA composites with cellulose nanofibers obtained by ultrasonication," BioRes. 6(1), 487-512.AbstractArticlePDF

    Cellulose nanofibers were obtained from microcrystalline cellulose (MCC) by the action of hydrodynamic forces associated with ultrasound. Nanofibers isolated from MCC by applying different ultrasonication conditions were characterized to elucidate their morpho-structural features by field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, and dynamic light scattering. Several differences were observed regarding the size of the nanofibers obtained in different ultrasonic conditions, but no significant changes in the crystalline structure of cellulose nanofibers were detected. The obtained cellulose fibers were used at low levels (1 to 5 wt.%) as reinforcements in a poly(vinyl alcohol) (PVA) matrix. The mechanical and thermal properties of the PVA/cellulose fibers nanocomposites films were determined. The tensile strength and modulus of the PVA film were significantly improved by the addition of cellulose nanofibers. Slightly higher onset degradation temperatures were obtained for PVA composites in comparison to neat PVA, showing an increase of the thermal stability caused by the addition of cellulose fibers.

  • Researchpp 513-528Martin-Sampedro, R., Eugenio, M. E., Revilla, E., Martín, J. A., and Villar, J. C. (2011). "Integration of kraft pulping on a forest biorefinery by the addition of a steam explosion pretreatment," BioRes. 6(1), 513-528.AbstractArticlePDF

    Steam explosion has been proposed for a wide range of lignocellulosic applications, including fractionation of biomass, pre-treatment of biomass for ethanol production, or as an alternative to conventional mechanical pulping. Nevertheless, a steam explosion process could also be used as pretreatment before chemical pulping, expecting a reduction in cooking time due to the open structure of the exploded chips. Thus, to evaluate the effect of steam explosion as a pretreatment in the kraft pulping of Eucalyptus globulus, steam exploded chips and control chips were subjected to kraft cookings. Steam exploded chips provided pulps with reductions of kappa number by up to 70% with no significant change in viscosity. Therefore, the cooking time could be shortened by 60%, increasing the productivity and obtaining pulps with similar delignification degree to those of the control pulp. Furthermore, not only the production rate could be increased, but also most of the hemicelluloses could be recovered before pulping and converted to a value-added product. Finally, although exploded pulp had inferior mechanical strength, the optical properties, which are more important in eucalyptus pulps, were found to be better.

  • Researchpp 529-536Ogundiran, M. B., Babayemi, J. O., and Nzeribe, C. G. (2011). "Determination of metal content and an assessment of the potential use of waste cashew nut ash (CNSA) as a source for potash production," BioRes.6(1), 529-536.AbstractArticlePDF

    The potential use of waste cashew nut shell (CNS) ash as a source for potash production was investigated in this study. Managing waste ash generated from cashew nut processing is a major challenge, as land filling and open dumping of the waste ashes have been the main options in management of the ash in Nigeria. Economically viable ways of using waste ash rather than having to dispose of it have to be investigated. The CNS was air-dried for 4 weeks and combusted to ashes; the resulting ash was extracted with water for its potash content. Some parameters of the CNS, including moisture, dry matter, and ash content, were determined. Potash yield obtained was 33.4% of 150 g CNS ash used; analysis of the potash gave it a percentage purity of 78%, while purity on recrystalization increased to 86%. Potash yield from CNS ash was comparable to those reported for wood ash, plantain peels, and other agro-wastes. Also, the results showed that the CNS shared similar lignocellulosic properties and characteristics with hardwood biomass.

  • Researchpp 537-551Munusamy, K., Somani, R. S., and Bajaj, H. C. (2011). "Tamarind seeds carbon: Preparation and methane uptake," BioRes. 6(1), 537-551.AbstractArticlePDF

    Tamarind seeds carbon (TSC) from tamarind (Tamarindus indica) seeds, an agro-byproduct and waste that is available abundantly in the southern states of India, was prepared by chemical activation with KOH. The influence of tamarind seeds char to KOH weight ratio (1:1 to 1:4) and activation temperature (400 to 800 °C) were investigated. TSC having micro-pore volume as high as 1.0 cm3/g with surface area 2673 m2/g was obtained. TSC was characterized by scanning electron microscopy, powder X-ray diffraction analysis, thermogravimetric analysis, and FT-IR spectroscopy. The potential of TSC to be used as a methane storage material was tested and compared with a commercial activated carbon. The highest methane adsorption capacity obtained for TSC was ca. 32.5 cm3/g at 30 °C and 1 bar. The maximum methane storage capacity achieved was 180 cm3/g at 30 °C and 35 bars.

  • Researchpp 552-569Bansal, N., Tewari, R., Gupta, J. K., Soni, R., and Soni, S. K. (2011). "A novel strain of Aspergillus niger producing a cocktail of hydrolytic depolymerising enzymes for the production of second generation biofuels," BioRes. 6(1), 552-569.AbstractArticlePDF

    The screening and isolation of fungi producing a cocktail of hydrolytic enzymes was studied. Among the various isolates obtained from different soil samples, a strain NS-2 was selected. The phylogenetic analysis of this strain showed highest homology (99%) with Aspergillus niger. It was capable of producing cellulolytic, hemicellulolytic, amylolytic, and pectinolytic enzymes in appreciable titers on wheat bran based liquid and solid state media. The mixture of enzymes produced by this organism could effectively hydrolyze various domestic waste residues, revealing conversion efficiencies of 89 to 92% and produced high reducing sugar yields of 0.48 to 0.66 g/g of dry residue. This enzyme cocktail could potentially find a significant application in the conversion of agricultural and other waste residues having cellulose, hemicellulose, starch, and pectin as carbohydrates to produce simpler sugars which can be fermented for the production of second generation biofuels.

  • Researchpp 570-583Mocchiutti, P., Galván, M. V., Inalbon, M. C., and Zanuttini, M. A. (2011). "Improvement of paper properties of recycled unbleached softwood kraft pulps by poly(allylamine hydrochloride), BioRes. 6(1), 570-583.AbstractArticlePDF

    Polyelectrolytes containing amine functional groups such as PAH (poly(allylamine hydrochloride)) can be useful, under certain conditions, for improving paper strength. In this work, the charge density of PAH was determined at different pH and ionic strengths; PAH adsorption onto the cellulosic fibers was characterized, and the effects of low PAH dosage on the papermaking properties were evaluated. It was found that the ionization of PAH is complete in acid media, but it is partial and depends on the ionic strength in neutral media. The adsorption isotherms of PAH on a recycled pulp from kraft liner allowed us to determine the amount needed to saturate the adsorption capacity of the fibers. For the three ionic strengths analyzed, the swelling of the fibers decreased when PAH was added in an amount corresponding to saturation (0.23% PAH on dried pulp). Nevertheless, the swelling was recovered when the amount of PAH was the double the saturation level (0.46% PAH on dried pulp). At these levels of addition, the papermaking properties were clearly improved, especially compressive strengths SCT (short compressive test) and CMT (concora medium test). The Page equation of tensile strength showed that PAH improved the shear bond strength, while the relative bonding area slightly decreased.

  • Researchpp 584-593Kord, B., Ismaeilimoghadam, S., and Malekian, B. (2011). "Effect of immersion temperature on the water uptake of polypropylene/ wood flour/ organoclay hybrid nanocoposite," BioRes. 6(1), 584-593.AbstractArticlePDF

    Polypropylene/wood flour/organoclay hybrid nanocomposites were melt-compounded in an internal mixer at 190 oC and 60 rpm rotor speed. Then samples were fabricated by injection molding. Effects of immersion temperature on the water uptake of hybrid nanocomposite were investigated. To meet this objective, water absorption of samples was determined after 24 h immersion in distilled water at different temperatures (25, 50, 75, and 100 °C). Results indicated that immersion temperature had a significant influence on the water absorption of composites. By increasing the temperature, water absorption increases as well. The maximum water absorption of composite is decreased by increasing the nanoclay and compatibilizer content. The morphology of nanoclay was determined by X-ray diffraction (XRD) and transmission electron microscopy. The effect of morphology on water absorption was also evaluated. Due to inadequate compatibilizer, exfoliated morphology of nanoclay was not obtained, but there was evidence of intercalation. The order of intercalation for samples containing 3 phc was higher than that of 6 phc at the same PP-g-MA content due to some agglomerations of organoclay.

  • Researchpp 594-605Zeng, J.-S., Chen, K.-F., and Li, J. (2011). "Study of the bulk density of high consistency pulp and engineering application in the bleaching tower," BioRes. 6(1), 594-605.AbstractArticlePDF

    From experimental simulation of the process of high consistency pulp moving in a bleaching tower, the aerated bulk density and packed bulk density were measured and studied by using a self-made experimental system. The scattered experimental data – pressure p, and bulk density difference, which was between packed bulk density and aerated bulk density (ρ-ρ0) – were fitted by using Matlab software, and some good-fitting regression curves and equations were obtained. The results showed there was a break point W in the regression curves; within the range 0 £ p £ W the relationship between (ρ-ρ0) and p was a linear function, while for W £ p £ 70000 the relationship was a power function. To effectively meet with the bleaching response for the different kinds and different consistencies of pulp in the tower, by using the fitting regression equations combined with the expressions of average bulk density and pressure in the tower caused by gravity-driven pulp, two equations for average packed density ρa were deduced with the aim of deciding the maximum volume value of the tower, in agreement with the sizes of the towers presently used by major companies.

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