Volume 8 Issue 2

The electrical properties of chicken feather fiber (CFF) and kenaf fiber (KF) unsaturated polyester (UP) composites have been studied with reference to fiber loading and frequency. Tests were carried out to compare the suitability of the two different composites as a dielectric material. The chicken feather fiber unsaturated polyester composite exhibited an overall lower dielectric constant, dissipation factor, and loss factor compared to the kenaf fiber unsaturated polyester composites. The values were high for the composites with fiber contents at 40%. The dielectric value increments were high at low frequencies, and they gradually reached significantly lower values at higher frequencies. Based on the results it was judged that chicken feather fiber composites would be suitable for application as high speed printed circuit board (PCB) material with good frequency stability at 1 MHz. Finally, an attempt was made to correlate the experimental values with theoretical calculations.

Three-step extraction of lignin fractions from ball-milled sugarcane bagasse (SCB) was studied with 96% dioxane, 50% dioxane, and 80% dioxane containing 1% NaOH at boiling temperature followed by purification to remove hemicelluloses. The total yields of hemicelluloses and lignin were 15.8% and 7.2% based on dried SCB, respectively. In the first step, 5.1% lignin (70.8% of the total extracted lignin) was isolated with 96% dioxane, which is higher than the traditional MWL procedure (3.3% lignin). In the second step, 10.4% hemicelluloses (65.8% of the total extracted hemicelluloses) were obtained with 50% dioxane. The obtained lignin fractions were characterized with FT-IR, 31P-NMR, and 2D 1H-13C HSQC. The results suggested that the ‘core’ of the lignin structure did not change dramatically during the sequential neutral and alkaline dioxane treatment processes. The contents of phenolic hydroxyl groups in the three lignin fractions based on 31P-NMR analysis were 1.66, 4.46, and 9.42 mmol/g lignin, respectively, higher than those from wood. The results also indicated that the lignin fractions obtained from SCB contained some amount of p-coumaric acid and ferulic acid, significantly different from those extracted from softwood and hardwood.

Domestic consumption of hardwood products in the United States since 2000 has trended downward, making exports the single most important market for higher grade hardwood lumber and a major market for higher value hardwood logs. Between 1990 and 2011, hardwood lumber exports increased by 46%. During most of this period, Canada was the largest export market for U.S. lumber, but in 2009 China/Hong Kong became the most important market. Nearly 60% of the lumber exported in 1990 was red or white oak, but the proportion of exports of these species had decreased to 38% by 2011. By contrast, exports of yellow-poplar lumber increased by 381% over this period. The volume of hardwood logs exported grew by 62% between 1990 and 2011, and Canada remained the largest customer. Several factors can affect the export of hardwood lumber and logs. In the 1990s, changes in exchange rates and economic activity in importing countries could be linked with changes in lumber and log exports. Since 2000, China, Vietnam, and other East Asian furniture-producing countries have become important export markets as overseas manufacturers seek lumber of species familiar to U.S. consumers. Conversely, the large decrease in hardwood lumber and log exports to Canada between 2006 and 2009 coincides with a similar decrease in wood furniture imports from Canada.

New, cost-effective source materials are being sought to enable the development of essential oils for potential use in pharmaceutical and commercial applications. The present study was aimed at investigating such features of Cupressus sempervirens, which despite its exotic legendary attributes has been almost ignored up until now. Gas liquid chromatography (GLC) was used to determine the various physico-chemical composition parameters (specific gravity, refractive index, acid and ester values profile) of the selected lignin-containing plant. The essential oil was extracted by a steam distillation technique using needles and twigs of C. sempervirens. The antimicrobial properties of the oil were investigated against a wide spectrum of microorganisms by flask culture and diffusion methods. In the flask culture method, only three strains, viz. A. niger, A. flavous, and A. fumigates, while in diffusion method seven strains, viz. A. niger, A. flavous, A. fumigatous, F. solani, F. oxysporum, Penecillium digitatum, and Candida uterus, and three strains of bacteria, viz. E. coli, M. leutius, B. lacto, exhibited 100% effectiveness in the presence of newly extracted C. sempervirens oil.

The aim of this paper was to predict the static bending modulus of elasticity (MOE_S) and modulus of rupture (MOR) of Scots pine (Pinus sylvestris L.) wood using three nondestructive techniques. The mean values of the dynamic modulus of elasticity based on flexural vibration (MOE_F), longitudinal vibration (MOE_LV), and indirect ultrasonic (MOE_US) were 13.8, 22.3, and 30.9 % higher than the static modulus of elasticity (MOE _S ), respectively. The reduction of this difference, taking into account the shear deflection effect in the output values for static bending modulus of elasticity, was also discussed in this study. The three dynamic moduli of elasticity correlated well with the static MOE _S and MOR; correlation coefficients ranged between 0.68 and 0.96. The correlation coefficients between the dynamic moduli and MOE _S were higher than those between the dynamic moduli and MOR. The highest correlation between the dynamic moduli and static bending properties was obtained by the flexural vibration technique in comparison with longitudinal vibration and indirect ultrasonic techniques. Results showed that there was no obvious relationship between the density and the acoustic wave velocity that was obtained from the longitudinal vibration and ultrasonic techniques.

Forest plantations of Salicaceae (poplars and willows) in Argentina are mainly used for the manufacture of pulp for newsprint. The rapid growth of these species results in a decrease in rotation age, which increases the proportion of juvenile wood. The aim of this work was to define the proportions of juvenile wood (JW) and mature wood (MW) of these species that can optimize the mechanical and optical properties of chemimechanical pulps for newsprint production. A two-component mixture type experimental design was used with proportions (JW:MW) of 0:100%, 25:75%, 50:50%, 75:25%, and 100:0%. When the mechanical properties were optimized, the highest desirability function was obtained with a JW:MW ratio of 100:0%, and the optimal ratio for optical properties was 0:100%. The pattern of variation of mechanical properties can be attributed to the higher density of MW, whilst that of the optical properties can be attributed to the higher content of extractives in the JW.

Kraft pulp produced from juvenile and mature wood from thirty-two-year-old Corymbia citriodora trees was evaluated. The stem was subdivided into regions of juvenile and mature wood, and then it was transformed into chips. These materials were then cooked in the Laboratory of Pulp and Paper at São Paulo State University (UNESP, Botucatu, SP, Brazil) and the physico-mechanical properties of the pulps were determined. The results showed that: (1) the pulp yields of mature wood were up to 4.4% greater in comparison to the juvenile wood, (2) the juvenile wood pulp required a shorter refining time than mature wood to reach the same Schopper-Riegler degree, (3) the juvenile wood pulp presented lower specific volume, and (4) the mature wood pulp presented greater air resistance, tensile, tear and burst index values, stress-strain factor, and stretch than the juvenile wood pulp.

The objective of this study was to determine the effects of certain fire-retardant chemicals on the combustion resistance of high-density fiberboard (HDF). Borax (BX), boric acid (BA), ammonium polyphosphate (APP), and alpha-x (AX) were added into the fibers made from 50% scots pine (Pinus sylvestris L.) and 50% beech (Fagus orientalis Lipsky) woods at 3%, 6%, and 9% levels based on oven-dry fiber weight. HDF panels were produced in 6.5 mm thickness. HDF panels’ combustion behavior was explored. To detect combustion resistance, the panels were tested according to the ASTM-E 69 and thermogravimetric analysis (TGA) tests. It was determined that fire-retardant (FR) chemicals enhanced the combustion resistance of the panels to varying degrees. As a result, the FR chemicals’ type and concentrations are effective for determining the combustion resistance of HDF panels.

Utilization of oil palm trunk waste for production of environmental friendly binderless particleboard was studied. Response surface methodology was used to optimize the manufacturing conditions. The steaming temperature (100 to 120˚C), steaming time (25 to 50 min), hot pressing temperature (180 to 220˚C), and hot pressing time (15 to 30 min) were optimized in the ranges shown. The optimum conditions for making the particleboard were found to involve steaming for 46 min at a temperature of 120˚C before it was compressed using a pressure of 12 MPa, at a temperature 215 ˚C for 29 min. The internal bond (IB) strength, modulus of rupture (MOR), thickness swelling (TS), and water absorption (WA) were 0.54 MPa, 8.18 MPa, 22%, and 51%, respectively. The residual values of actual and model-based calculated IB, MOR, TS, and WA were found to be 0.1 MPa, 0.23 MPa, 2%, and 4%, respectively, which shows the significance of the study.

The use of chemithermomechanical (CTMP) pulp from rapeseed residues as raw material for the manufacturing of linerboard and fluting medium grades was investigated. For this purpose, different alternatives for improving mechanical and optical properties of rapeseed CTMP were studied, and the addition of nanofibrillated cellulose (NFC) was proposed to decrease the intensity of the beating process and enhance the final mechanical properties. Handsheets from each pulp were produced, and their properties compared to those of linerboard from recycled paper. Compared to kraft linerboard from recycled paper, rapeseed CTMP required less beating to reach an optimal breaking length. This reduction in beating can be combined with the addition of NFC to improve the mechanical properties of paper. Therefore, rapeseed CTMP from crop residues is a technically affordable alternative for the production of fluting and linerboard grades.