Volume 8 Issue 4

In Central Europe the main species that are used for the production of sawn wood are spruce, pine, and European beech. After the sawing process, the sawn timber is technically dried to a certain moisture content by means of condensation drying. The water movement in the cellular structure, which is caused by the drying process, draws some of the extractives into solution. In the process of kiln drying, hot air evaporates the water and the dissolved extractives. Some of the water condenses on the floor and the walls of the kiln, while the rest is blown out with the steam. Therefore, condensate was taken from the bottom of the kiln as well as from the energy recovery system. A chemical analysis by means of purge-and-trap showed the presence of volatiles that could be classified as typical for the wood materials from which they originated under the conditions of high temperature and high moisture content.

Unbleached kraft pulp fibers were modified with laccase and ferulic acid (FRC) to improve their physical strength properties in paper products. The optimal conditions of laccase-FRC modification were examined in terms of the physical properties of pulps. The effects of laccase-FRC modification on the carboxyl group content and surface lignin content of pulps were investigated. The surface morphologies of laccase-FRC-modified pulp fibers were observed by atomic force microscopy (AFM). The carboxyl group and surface lignin contents for laccase-FRC-modified pulps increased compared to the control pulp. AFM phase images showed that the laccase-FRC-modified fiber surfaces were covered with large granular substances from the products of FRC grafting and lignin polymerization/condensation reactions. The observed

Three tannin-based foam formulations differing in the type of surfactant added were tested during foaming via simultaneous monitoring of the variation in temperature, foam rising rate, internal foam pressure, and dielectric polarization, the latter being a direct measure of the setting and curing of a thermosetting foam. This monitoring is an effective descriptor of the process and possible characteristics of the foam being prepared and constitutes an invaluable tool for foam formulation. The addition of a surfactant was shown to have a major effect on foam dynamics by retarding the onset of cross-linking to a lesser or greater extent in relation to the peak of maximum temperature in self-blowing foams. Cationic surfactants, or non-ionic surfactants capable of transforming into cationic species under the acidic environmental conditions used for tannin-based foams, were found to retard cross-linking more markedly than did non-ionic surfactants.

Binary bio-composites of acorn shell (AS) and low density polyethylene (LDPE) were prepared via a twin-screw extruding method. The mechanical properties of the composites decreased with increasing AS content, and all composites maintained similar tensile strength as expected based on the Nicolais-Narkis model, indicating weak adhesion between AS and LDPE. The effects of three compatibilizers, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA), and maleic anhydride grafted polyethylene (PE-g-MAH) on the composites were also studied. The results showed that the three compatibilizers improved the mechanical properties of composites at different levels, and the PE-g-MAH compatibilizing system showed the best mechanical strength, which was increased by about 80% from that of the control. Micro-morphologic investigation revealed a rough fractured surface, indicating that the addition of compatibilizers improved the interfacial bonding properties of the matrix materials LDPE matrix. Dynamic mechanical thermal analysis (DMA) further confirmed that the addition of compatibilizers significantly improved the compatibility of blending components and changed the properties of LDPE matrix materials.

Green composites are gradually replacing general plastics to achieve the aim of environment sustainability. In the present study, both compatibilized and uncompatibilized recycled polypropylene (RPP) and peanut shell powder (PSP) composites were prepared. The effect of various PSP loadings (0 to 40% by weight) on the processing, tensile properties, morphology, Fourier transform infrared (FTIR) analysis, and water uptake properties were examined. The results showed that the incorporation of PSP caused an increase in stabilization torque, tensile modulus, and water absorption, but lowered the tensile strength and elongation at break of the RPP/PSP composites. Compatibilized RPP/PSP composites with poly(ethylene-co-acrylic acid) (PEAA) significantly enhanced the tensile properties while decreasing the water absorption of RPP/PSP composites. FTIR analysis revealed a slight change in band positions and intensities, indicating a distinct interaction between the chains of polymers. SEM micrographs showed the interaction between PSP and the matrix.

In this study, old corrugated container (OCC) pulp was added in different ratios (5%, 10%, 15%, 20%, and 25% w/w) to unbleached virgin pulps of both European black pine and Scots pine, and its effects on paper properties were investigated. As a control, OCC pulp-free handsheets were separately produced from European black pine and Scots pine pulps. The results indicated that the addition of OCC pulp decreased the strength properties, except for the tear index, of the handsheets. In addition, compared to the control handsheets, the paper containing the OCC pulp displayed higher air permeability. The results showed that up to 10% of the virgin softwood kraft pulp could be replaced with OCC pulp without bringing about considerable loss of strength. Also, this ratio of OCC addition could be suitable for production of wrapping papers.

The influence of particle size and an alkaline pretreatment on the anaerobic digestion of corn stover was studied. Four particle sizes, 0.075 to 0.25, 0.25 to 1.0, 1.0 to 5.0, and 5.0 to 20.0 mm, were used. The highest and lowest methane yields were obtained from untreated corn stover at particle sizes of 0.25 to 1.0 and 5.0 to 20.0 mm, respectively. 4% NaOH and 2% Ca(OH)2 (combined alkaline pretreatment, CAP) were then used together to pretreat corn stover at these two particle sizes, compared with 6% NaOH pretreatment (single alkaline pretreatment, SAP). The cumulative methane yields from particle sizes 0.25 to 1.0 mm after CAP, 0.25 to 1.0 mm after SAP, 5.0 to 20.0 mm after CAP, and 5.0 to 20.0 mm after SAP were 286.9, 287.0, 268.7, and 272.6 mLg^-1 VS, respectively. The particle size barely influenced the final cumulative methane yield of alkali-treated corn stover. Moreover, the cumulative methane yield of the corn stover after CAP was comparable with that of the corn stover after the SAP under the same conditions. These results provide us with a promising substitute of NaOH pretreatment for corn stover bioconversion in the future.

Bleached simao pine kraft pulp was treated with Aspergillus niger crude cellulase produced by submerged fermentation using the pulp as the carbon source. The effects of the cellulase on the pulp beatability and mechanical properties were studied. Fourier transform infrared spectroscopy (FT-IR) was performed to study the effect of cellulase treatment on the cellulose crystallinity index. The fiber morphology difference before and after treatment was also revealed by atomic force microscope observation. Compared to the control pulp, the beating time of the cellulase-treated pulp with the dosage of 7 u/g could be reduced from 360 s to 260 s under the same beating degree of 48 °SR, which indicates a savings of about 28% beating energy consumption. The cellulase treatment had negative impacts on the pulp’s mechanical properties. The cellulase preferentially adsorbed on the fine surface. The cellulose amorphous region was easier to treat with cellulase than the crystalline region. Atomic force microscope images demonstrated that the primary wall of fibers was peeled off and the S1 layer of fibers came to the surface after the cellulase treatment.

This study evaluated the properties of fluting paper made with a blend of unbleached bagasse soda pulp (340 mL CSF freeness) and OCC pulp (250 to 300 mL CSF freeness) of 0:100, 10:90, 30:70, 50:50, 70:30, and 90:10 ratios by weight, respectively. Some handsheets at 120 g/m2 basis weight were made. Strength characteristics such as tear index, tensile index, air resistance, double folds, burst index, and Concora medium test (CMT) were measured according to TAPPI and ISO standards and compared to each other. Inferior handsheet properties were observed when using 100% recycled fibers. Results further showed that addition of 10 to 30% bagasse pulp to OCC pulp did not significantly enhance the sheet strength of the product compared with the control sample (100% OCC pulp). However, it was found that addition of 70% or more of virgin pulp to the OCC pulp resulted in a substantial increase in the strength properties, except for the tear index. The modification of the fibers was visually evaluated by Scanning Electron Microscope (SEM). Overall, the results showed that flexible virgin bagasse fibers can be used as a lignocellulosic fiber for making fluting paper in combination with recycled OCC fibers.

Novolak-type resins were produced via liquefaction of oil palm empty fruit bunch (EFB) fibres with various liquefaction and resinification parameters such as temperature, time, catalyst concentration, and phenol-to-EFB ratios, and investigated in terms of flow properties (melt viscosity and melt flow rate) of the phenolated EFB (PEFB) and resinified PEFB (RPEFB). The results showed that the phenol/EFB ratio was the most effectual parameter in the variation of melt viscosity and melt flow rate (MFR) of PEFB. The melt flow rate of the PEFB was tremendously lower than that of the commercial novolak resin. The results showed that the activation energy for flow, which was obtained using the Arrhenius equation, increased when the liquefaction temperature increased. The results also demonstrated that the molten PEFB showed a shear thinning or pseudo-plastic behavior.