NC State
  • Editorialpp 6902-6903Wu, D., Qian, X., and Shen, J. (2017). "Macromolecular reorganization as a basis for converting cellulosic hydrogels into sustainable plastics," BioRes. 12(4), 6902-6903.AbstractArticlePDF

    The development of lignocellulose-derived sustainable plastics is an important strategy for a greener future. Cellulosic hydrogels, which are readily generated from a cellulosic source (e.g., wood pulp), can be converted into high-strength plastics by hot-pressing. In this process, cellulose macromolecules are fluidized and reassembled, leading to significant change of bonding interactions and structural characteristics. This interesting concept would open the door for new possibilities of bioproduct design.

  • Editorialpp 6904-6906Hubbe, M. (2017). "To repair or not to repair cracked wood," BioRes. 12(4), 6904-6906.AbstractArticlePDF

    If only wood could be defect-free, then the minimum strength of solid-wood beams and other structures could be much higher. Structural failures could be avoided, and-or less material might be required in some applications. Cracks in wooden structures can be filled with adhesives or with thermoplastic composite material. But to approach the intended strength of defect-free wood, it is necessary to use other strategies such as glued rods and surface patches. The ultimate answer may lie in better species selection, tree breeding, forestry strategies, lumber cutting practices, and lumber drying practices to avoid cracks in the first place.

  • Researchpp 6907-6923Carvalho, D. M., and Colodette, J. L. (2017). "Comparative study of acid hydrolysis of lignin and polysaccharides in biomasses," BioRes. 12(4), 6907-6923.AbstractArticlePDF

    Effects of different acid hydrolysis conditions were studied relative to the chemical transformations of lignin in eucalyptus, sugarcane bagasse, and sugarcane straw, and on the transformations of multiple polysaccharides in eucalyptus. The acid hydrolysis using 12 mol/L sulfuric acid followed by acid hydrolysis using approximately 0.41 mol/L sulfuric acid was used as the reference for the lignin and sugar analysis. During acid hydrolysis, the relative amount of lignin increased with longer reaction times and/or greater acid concentrations for all biomasses. The overestimation of lignin in harsher acidic conditions resulted from the summation of lignocellulosic-derivatives (pseudo-lignin) together with lignin itself. Lignin reactions (dissolution/deposition) for bagasse and straw occurred in a greater extent than for eucalyptus, considering similar conditions of acid hydrolysis. The sugar transformation during acid hydrolysis was also investigated for eucalyptus. The sugar content quantified in eucalyptus decreased as the acid concentration and/or reaction time in the second hydrolysis increased. Glucose, galactose, and mannose were more resistant to harsher acidic conditions than xylose and arabinose. However, the most severe conditions (121 ºC, 90 min, and 6.15 mol/L H2SO4) caused complete sugar degradation.

  • Researchpp 6924-6955Bekiroğlu, S., Mertoğlu Elmas, G. M., and Yagshiyev, Y. (2017). "Contribution to sustainability and the national economy through recycling waste paper from Istanbul’s hotels in Turkey," BioRes. 12(4), 6924-6955.AbstractArticlePDF

    Obtaining cellulose from recyclable waste paper contributes to the sustainability of forest resources, water and energy savings, and the reduction of environmental pollution. However, waste paper collected under inappropriate conditions for recycling can be degraded in a short time, thus becoming economically useless. This study examined the factors affecting source-separated collection processes of waste paper in Istanbul hotels, as well as the correlation among these factors. The economic value of the assumed benefits of source-separated waste paper was also calculated. To achieve these objectives, various inputs and methods were used, including the percent tabulation technique and the chi-square independence test. As a result, it was determined that 70% of managers and employees of Istanbul hotels were sensitive to recycling waste paper, but they were not aware of the entire benefits of waste paper recycling. It was also determined that because of waste paper recycling, 18 thousand trees, 5 million kWh of electricity, 3 thousand tons of water, and 1.3 thousand tons of fuel oil were saved, and the generation of 27 thousand tons of CO2 was prevented annually. Hotels in Istanbul provide the economy with an annual average of 752 tons of waste paper, which corresponds to 78% of the foreign trade deficit of Turkey’s paper and paper products sector in the last five years.

  • Researchpp 6956-6970Wang, X., Liu, Z., Wang, S., Kong, F., Yang, G., Fatehi, P., and Lucia, L. A. (2017). "Enhancing the alkaline peroxide mechanical pulp strength by cationization with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride," BioRes. 12(4), 6956-6970.AbstractArticlePDF

    Alkaline peroxide mechanical pulp (APMP) is a newly emerging high yield pulp (HYP) with numerous advantages. However, the drawback of the alkaline peroxide mechanical pulp from untreated plant biomass is its poor network strength. In this work, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) modification was proposed to enhance pulp network strength by fiber surface modification that could enhance fiber bonding. Three factors were analyzed by response surface methodology (RSM) to optimize treatment conditions based on factorial designs. The results showed that the optimal conditions were CHPTAC dosage of 0.8% (oven-dry pulp), NaOH dosage of 0.1% (oven-dry pulp), and pulp concentration of 8%. The modified pulp fibers were characterized by elemental analysis, charge density analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA), and internal bond strength analysis, as well as zero span tensile analysis. The physical strength of the modified APMP pulp was increased in terms of tensile index, tear index, and burst index. After modification, the tensile index, tear index, and burst index increased by 35.3%, 29.2%, and 16.7% respectively. The internal bonding strength increased by 144.4%; however, the increase of zero span tensile index of modified pulp fibers was insignificant.

  • Researchpp 6971-6983Altuntas, E., Narlioglu, N., and Alma, M. (2017). "Investigation of the fire, thermal, and mechanical properties of zinc borate and synergic fire retardants on composites produced with PP-MDF wastes," BioRes. 12(4), 6971-6983.AbstractArticlePDF

    Synergic effects of different fire retardant compounds and zinc borate on wood-plastic composites filled with polypropylene (PP) and medium-density fiberboard (MDF) waste fibers were investigated. For this purpose, zinc borate, synergic compounds (antimony trioxide, ammonium phosphate, and magnesium hydroxide), and a coupling agent, i.e., maleic anhydride-grafted polypropylene (MAPP), were used in the production of wood-plastic composites (WPCs). The composite samples were characterized in terms of the burning rate and limiting oxygen index (LOI) analyses, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) along with mechanical tests, i.e., flexural properties, tensile properties, elasticity modulus, and impact strength. It was found that the synergic influence of the combination of zinc borate, antimony trioxide, and magnesium oxide on WPCs increased the heat resistance according to the burning rate, LOI, TGA, and DSC tests. Also, the mechanical properties of the WPCs decreased slightly, but their elasticity modulus increased.

  • Researchpp 6984-7001Gopinathan, P., Subramanian, K., Paliyath, G., and Subramanian, J. (2017). "Genotypic variations in characteristics of nano-fibrillated cellulose derived from banana pseudostem," BioRes. 12(4), 6984-7001.AbstractArticlePDF

    A laboratory study was undertaken to extract nano-fibrillated cellulose (NFC) from the pseudostem (a waste from the fruit harvest) of two commercial banana cultivars (‘Grand Naine’ and ‘Poovan’) in Tamil Nadu using a novel approach: a one-step method with a bleaching agent and alkali-free acid hydrolysis coupled with ultrasonication. The acid hydrolysis was performed using nitric acid and acetic acid (1:10 ratio). The treatment was effective in the depolymerization and defibrillation of banana pseudostem fiber and in the formation of NFC, which was confirmed by several physico-chemical techniques. The average diameters of the nanofibrils were 6 to 8 nm and 4 to 6 nm for ‘Grand Naine’ and ‘Poovan’, respectively. The XRD analysis revealed an increased cellulose crystallinity of almost 20% in the NFC compared with the respective raw banana fibers. The Fourier transform infrared (FT-IR) spectroscopy and thermal gravimetric analysis (TGA) confirmed the absence of lignin, hemicelluloses, and pectin in the nano-fibrillated samples. The thermal analysis showed the increased thermal stability of the NFC.

  • Researchpp 7002-7015Huang, W., Wang, E., Chang, J., Wang, P., Yin, Q., Liu, C., Zhu, Q., and Lu, F. (2017). "Effect of physicochemical pretreatments and enzymatic hydrolysis on corn straw degradation and reducing sugar yield," BioRes. 12(4), 7002-7015.AbstractArticlePDF

    Straw lignocelluloses were converted to reducing sugar for possible use for bioenergy production via physicochemical pretreatments and enzymatic hydrolysis. The experiment was divided into 2 steps. The first step focused on breaking the crystal structure and removing lignin in corn straw. The lignin, hemicellulose, and cellulose degradation rates observed were 92.2%, 73.7%, and 4.6%, respectively, after corn straw was treated with sodium hydroxide (3% w/w) plus high-pressure steam (autoclave), 74.8%, 72.5%, and 4.3% after corn straw was treated with sodium hydroxide (8%, w/w) plus wet steam explosion, compared with native corn straw (P < 0.05). The second step was enzymatic hydrolysis for the pretreated straw. The enzymatic hydrolysis could yield 576 mg/g reducing sugar and significantly degrade cellulose and hemicellulose contents by 93.3% and 94.4% for the corn straw pretreated with sodium hydroxide plus high-pressure steam. For the corn straw pretreated with sodium hydroxide plus wet steam explosion, the enzymatic hydrolysis could yield 508 mg/g reducing sugar, and degrade cellulose and hemicellulose contents by 83.5% and 84.2%, respectively, compared with the untreated corn straw (P<0.05). Scanning electron microscopy showed that the physicochemical pretreatments plus enzymatic hydrolysis degraded corn straw to many small molecules. Thus, physicochemical pretreatments plus enzymatic hydrolysis converted lignocellulose to reducing sugar effectively.

  • Researchpp 7016-7031Záborský, V., Borůvka, V., Kašičková, V., and Ruman, D. (2017). "Effect of wood species, adhesive type, and annual ring directions on the stiffness of rail to leg mortise and tenon furniture joints," BioRes. 12(4), 7016-7031.AbstractArticlePDF

    The effects of selected factors, wood species (Fagus sylvatica L. and Picea abies L.), type of joint (haunched mortise and tenon, and haunched dovetail mortise and tenon), tenon thickness (one-third and half-joint thickness), type of adhesive (polyvinyl acetate and polyurethane adhesive), loading type (compressive and tensile), and direction of the annual rings were evaluated relative to the elastic stiffness. The testing samples were loaded by bending moment with tensile and compressive forces in the angular plane. The wood species, type of joint, tenon dimension, and type of adhesive all had a statistically significant effect on the elastic stiffness. However, the interaction of those factors was statistically insignificant. The loading type and direction of the annual rings did not have a significant effect on the elastic stiffness. For spruce, the use of mortise and tenon with a toothed feather (MTTF) was found to be disadvantageous, whereas the use of a toothed feather was favorable for beech. Half thickness of the joint was always an advantage, such that the stiffness increased. For spruce joints, the type of glue was not important, whereas for beech, the stiffness of joints glued with PVAc was significantly higher than with PUR adhesive.

  • Researchpp 7032-7040Nosek, R., Holubcik, M., Jandacka, J., and Radacovska, L. (2017). "Analysis of paper sludge pellets for energy utilization," BioRes. 12(4), 7032-7040.AbstractArticlePDF

    The pulp and paper industry in Europe produces over 11 million tons of waste per year. Given high landfill operational costs, thermal co-processing with biomass may be a viable management and valorisation option for such wastes. In this work, the analysis of biomass (wood sawdust), mixture of primary and secondary pulp mill sludge and their respective blends (50 wt.%, 60 wt.%, 70 wt.% of sludge) was assessed by thermogravimetric analysis. One of the possibilities to ensure valorisation of paper pulp mill sludge is its combustion in the form of pellets containing a different amount of sludge. Production of pellets samples was realised on laboratory experimental device. The measurements showed that increasing the content of paper sludge in the produced pellets reduced the calorific value and increased the ash content. This research deals also with the effect of paper sludge on the ash melting temperatures. The results indicated that a higher content of paper sludge in the pellets increased the ash melting temperatures. This advantage of paper sludge can be utilized in co-combustion of biomass with a low ash melting temperature.