NC State
  • Editorialpp 4491-4492Zawistoski, P. S. (2012). "Time for a forum on terms used for textile fibers," BioRes. 7(4), 4491-4492.AbstractPDF
    The advances in manufactured fibers and textiles have garnered interest and excitement of textile artists and consumers alike for a myriad of reasons, including health, environmental, and fashion. The chemical and molecular nature of these advances, however leads to confusion and misunderstanding of the new fibers in the materials. This is exacerbated by the current climate of distrust for chemical words and desire for "green" products and the unregulated (mis)information and marketing on the web. Textile artists, consumers, and the clothing and household textile industry need clear names and labels to identify the materials they are using.
  • Editorialpp 4493-4494Ding, Y., Zhu, S., Yu, P., Cheng, S., and Wu, Y. (2012). "Can lignocellulosic hydrocarbon liquids rival lignocellulose-derived ethanol as a future transport fuel?" BioRes. 7(4), 4493-4494.AbstractPDF
    Although transport fuels are currently obtained mainly from petroleum, alternative fuels derived from lignocellulosic biomass (LB) have drawn much attention in recent years in light of the limited reserves of crude oil and the associated environmental issues. Lignocellulosic ethanol (LE) and lignocellulosic hydrocarbons (LH) are two typical representatives of the LB-derived transport fuels. This editorial systematically compares LE and LB from production to their application in transport fuels. It can be demonstrated that LH has many advantages over LE relative to such uses. However, most recent studies on the production of the LB-derived transport fuels have focused on LE production. Hence, it is strongly recommended that more research should be aimed at developing an efficient and economically viable process for industrial LH production.
  • Editorialpp 4495-4498Shen, J., and Qian, X. (2012). "Use of mineral pigments in fabrication of superhydrophobically engineered cellulosic paper," BioRes. 7(4), 4495-4498.AbstractPDF
    Superhydrophobic materials have a lot of interesting potential applications. The self-cleaning property is a unique feature. Rendering the water-loving cellulosic paper superhydrophobic can open the door for value-added applications. Superhydrophobic paper is a fairly new area, and only very limited scientific publications are available in the literature. Among these publications, the topics on the use of mineral pigments in fabrication of superhydrophobic structures account for a large proportion. During the fabrication process, mineral pigments, e.g., silica, precipitated calcium carbonate, and clay, generally need to be hydrophobized, either directly or indirectly. Mineral pigments can be applied to cellulosic paper by surface treatment or wet-end filling, and good dispersabilities of these pigments are always highly demanded. A key mechanistic point is that by tunable particle packing or fabrication, mineral pigments may exhibit surface-roughening effects, which are critical for superhydrophobicity development. The roughening of a hydrophobic surface helps to enhance hydrophobicity. Possible concepts such as nano-structuring or controllable surface patterning of mineral pigments may help to improve superhydrophobicity. Environmental friendliness will also guide the scientific/technical development in this area.
  • Editorialpp 4499-4500Hubbe, M. A. (2012). "The Wood Age - Part of our past, but should we wish for it as our future?" BioRes. 7(4), 4499-4500.AbstractPDF
    A new book by Radkau, Wood. A History, provides telling insight into the cleverness and also into the short-sightedness of humans in their almost uninterrupted dependence on forest resources. This essay touches upon the earliest evidence of prehistoric wood-based technologies – showing examples where humans have tended, in many generations, to exhaust their readily available resources. Beginning in the Industrial Revolution a greatly expanded usage of first coal and the petroleum have tended to take some of the pressure off of the use of wood as a fuel source. But there are early signs that the situation may be changing soon. Large wood-to-liquid-fuel facilities are being talked about. Though the usage of wood for fuel has the potential to be a sustainable enterprise, human history suggests we should exercise caution.
  • Researchpp 4501-4516Westerberg, N., Sunner, H., Helander, M., Henriksson, G., Lawoko, M., and Rasmuson, A. (2012). "Separation of galactoglucomannans, lignin, and lignin-carbohydrate complexes from hot-water-extracted Norway spruce by cross-flow filtration and adsorption chromatography," BioRes. 7(4), 4501-4516.AbstractPDF
    A simple method to simultaneously recover polymeric carbohydrates, mainly galactoglucomannans (GGM), lignin, and lignin-carbohydrate complex (LCC) from hot-water-extracted Norway spruce wood is presented. The isolation method consists of cross-flow filtration, where high and low molecular mass species are removed, followed by fixed-bed adsorption on a hydrophobic polymeric resin (XAD-16) to remove lignins and lignans. In the second step of fixed-bed adsorption, a phenylic reversed-phase analytical chromatography column, where mass transport resistance is minimized and a very high selectivity towards aromatic compounds have been observed, was used to separate LCC from GGM. The isolated LCC fraction contained about 10% aromatics, whereas the upgraded GGM fraction contained about 1.5% aromatics and the lignin fraction contained about 56% aromatics. Polymeric xylan was accumulated in the GGM fraction, while mannose was the dominant sugar found in the LCC fraction. As products, approximately 7% was recovered in the lignin fraction in the first adsorptive step, 5% was recovered as LCC, and 88% as upgraded hemicelluloses.
  • Researchpp 4517-4530Song, Y., Li, Q., Zhao, X., Sun, Y., and Liu, D. (2012). "Production of 2,3-butanediol by Klebsiella pneumoniae from enzymatic hydrolyzate of sugarcane bagasse," BioRes. 7(4), 4517-4530.AbstractPDF
    Fermentation conditions for 2,3-butanediol (2,3-BD) production by Klebsiella pneumoniae CGMCC1.9131 were optimized statistically in shake flasks. Four significant factors including the initial concentrations of yeast extract, glucose, K2HPO4, and (NH4)2SO4 were optimized by Response Surface Methodology (RSM). To further improve the yield of 2,3-BD, EDTA Na2 was added to the medium. After optimization, the yield of 2,3-BD was 0.44 g/g glucose and the final concentration was 26.20 g/L when initial glucose concentration was 60 g/L. The enzymatic hydrolyzate of pretreated sugarcane bagasse by alkali-peracetic acid (PAA) and dilute acid were further used as feedstock to produce 2,3-BD under the optimized conditions, and the yields of 2,3-BD were 0.36 and 0.43 g/g consumed sugars, respectively. The experimental results indicated that the enzymatic hydrolyzate could be well converted to 2,3-BD.
  • Researchpp 4531-4544Zhang, H., Wu, S., Zhang, J., and Li, B. (2012). "Production of furans from pulp sheet over sulfated solid acid catalysts," BioRes. 7(4), 4531-4544.AbstractPDF
    Furans are high value-added biomass-derived chemicals that can be used to replace petrochemicals. In this study, sulfated solid acid catalysts were prepared by precipitation and impregnation and were used for the conversion of a cellulosic pulp sheet into furans. The physicochemical properties of the prepared sulfated solid acid with different calcination temperatures and different mol ratios of Ti-Al were characterized using XRD, elemental analysis, TG, and NH3-TPD. Furthermore, the effects of various processing parameters such as temperature, time, and catalyst dosage on the reaction performance were studied. The combined yield of 5-hydroxymethyl-furfural and furfural reached 8.9% and 4.5% of pulp sheet mass with a 5% dosage of SO42-/TiO2-Al2O3 catalyst at 220 °C for 30 min. The activity for recovered catalyst was also investigated in this study.
  • Researchpp 4545-4562Ab. Wahab, N. H., Md. Tahir, P., Beng Hoong, Y., Ashaari, Z., Mohd Yunus, N. Y., Uyup, M. K. A., and Shahri, M. H. (2012). "Adhesion characteristics of phenol formaldehyde pre-preg oil palm stem veneers," BioRes. 7(4), 4545-4562.AbstractPDF
    The purpose of this study was to evaluate the adhesion properties of phenol formaldehyde-prepreg oil palm veneers that have potential for plywood manufacture. Phenol formaldehyde (PF) resin of three different molecular weights (i.e. 600 (low), 2,000 (medium), and 5,000 (commercial)) were used to pre-treat the veneers. The veneers were soaked in each type of PF resin for 20 seconds, pressed between two rollers, and pre-cured in an oven maintained at 103 ± 2 °C for 24 hours. The volume percent gain (VPG), weight percent gain (WPG), pH, buffering capacity, and contact angle of the phenolic pre-preg veneers were determined. The bonding shear was also evaluated according to British Standard European Norm BS EN 314. The results show that veneers from both inner and outer layers treated with low molecular weight PF (LMwPF) resin had significantly higher VPG and WPG compared to the other PF resins. The pH values of all of the veneers were slightly acidic (6.5 to 6.8) except for those that were treated with commercial molecular weight PF resin (7.8). A buffering capacity study revealed that untreated veneer had a greater resistance toward alkali, but was unstable under acidic conditions, while the phenolic pre-preg veneer behaved differently. This effect was more prominent as the molecular weight of the PF resin increased. An examination of the veneer surfaces demonstrated that phenolic treatment had increased the contact angle of the OPS veneer surfaces significantly. The bonding properties of plywood made from pre-preg palm veneers were found to be superior to those of commercial palm plywood.
  • Researchpp 4563-4574Huang, R., Zhang, Y., Xu, X., Zhou, D., and Wu, Q. (2012). "Effect of hybrid mineral and bamboo fillers on thermal expansion behavior of bamboo fiber and recycled polypropylene-polyethylene composites," BioRes. 7(4), 4563-4574.AbstractPDF
    The effect of bamboo and hybrid bamboo-precipitated calcium carbonate (PCC) fillers on thermal expansion behavior of filled plastic composites was investigated. The linear coefficient of thermal expansion (LCTE) of the filled composites decreased with increased PCC and bamboo filler loading levels. The composite system with refined bamboo fibers (RBFs) had smaller LCTE values compared with those from the systems with ground bamboo particles (GBPs). The use of silane treatment on bamboo fiber/particle surface helped enhance its bonding to the plastic matrix, leading to a further reduction of LCTE values for both GBP and RBF composite systems. The observed behavior of reduced LCTE is attributed to a small filler LCTE value, reduced overall plastic volume, and enhanced interfacial bonding with treated bamboo materials. Thus, hybrid bamboo and PCC fillers are suitable materials for reducing the thermal expansion of the composites caused by temperature changes.
  • Researchpp 4575-4585Segerholm, B. K., Ibach, R. E., and Westin, M. (2012). "Moisture sorption, biological durability, and mechanical performance of WPC containing modified wood and polylactates," BioRes. 7(4), 4575-4585.AbstractPDF
    Biological durability is an important feature for wood-plastic composites (WPC) intended for outdoor applications. One route to achieving WPC products with increased biological durability is to use wood preservative agents in the formulation of the WPC. Another option could be to use a chemically modified wood component that already exhibits increased resistance to biological degradation. There is also a need to use biobased thermoplastics made from renewable resources, which would decrease the dependency on petrochemically-produced thermoplastics in the future. The objective of this study was to examine moisture sorption properties, biological durability, and mechanical performance of injection-molded WPC samples based on acetylated or thermally modified wood components and a polylactate matrix. The biological durability was evaluated in a terrestrial microcosm (TMC) test according to ENV 807, followed by mechanical evaluation in a center point bending test. The moisture sorption properties were investigated via both water soaking and exposure in a high-humidity climate. Low or negligible mass losses were observed in the TMC test for all WPC samples. However, the mechanical evaluation after exposure in the TMC test showed 35-40% losses in both strength and stiffness for the WPC containing an unmodified wood component.