Volume 11 Issue 1

Laboratory-designed continuous steam explosion (CSE) equipment was used to prepare continuous steam-exploded eucalyptus fibers (CSEEFs). The pretreatment intensity was varied by changing treatment time, and effects of CSE on the composition, microstructure, surface composition, thermal properties, and crystallinity of CSEEFs were investigated. Composition analysis showed that CSE had a significant impact on lignin and hemicellulose, but little on cellulose. Scanning electron microscopy indicated that the middle lamella, primary wall, and outer secondary wall were progressively stripped as the CSE time increased. X-ray photoelectron spectroscopy demonstrated that concentrations of extractives and lignin were higher on the surface of eucalyptus wood than CSEEFs’, and the exposed carbohydrate fraction increased with increasing CSE time. Differential scanning calorimetry showed that eucalyptus wood has one glass transition (193.5 °C), whereas two glass transitions at 56.7 and 138.5 °C were observed for CSEEF-5. X-ray diffraction results suggested that crystallinity of samples decreased with increasing CSE time. Thermogravimetric analysis showed the pyrolysis peak temperature of samples first increased and then decreased slightly as CSE time increased. These data will be useful for the optimization and application of CSE technology.

Activated carbon derived from biomass waste, namely palm shell, was evaluated as a potential adsorbent for the removal of Reactive Black 5 dye (RB5) from an aqueous solution. This work focused on the equilibrium isotherms and the kinetics of the adsorption process. Batch adsorption tests were conducted to determine the effects of various parameters, such as contact time, RB5 concentration, adsorbent dose, temperature, and initial solution pH, on the treatment performance. The adsorption capacity of the adsorbent used in the study was higher in an acidic medium. The Langmuir model provided the best fit for the obtained equilibrium isotherm data, while the adsorption kinetics was best represented by the pseudo-first-order model. RB5 adsorption was endothermic in nature, with an activation energy of 12.6 kJ/mol. The maximum adsorption capacity of the adsorbent was 25.1 mg/g at pH 2. Palm shell-based activated carbon is shown to have great potential in the adsorption of RB5 from aqueous solution.

The objectives of this work were to investigate the effect of kenaf fiber alignment on the mechanical and fatigue properties of kenaf/glass hybrid sandwich composites. Three types of kenaf fibers were used, namely, non-woven random mat, unidirectional twisted yarn, and plain-woven kenaf. A symmetric sandwich configuration was constructed with glass as the shell and kenaf as the core with a constant kenaf/glass weight ratio of 30/70% and a volume fraction of 35%. Tensile, compression, flexural, and fully reversed fatigue tests were conducted, and a morphological study of the tensile failure surface of each hybrid composite was carried out. The non-woven mat kenaf hybrid had poor properties for all tests, while the unidirectional kenaf hybrid composite possessed higher tensile strength and similar compressive properties compared with the woven kenaf. Hybridization with kenaf fibers improved the fatigue degradation coefficient of the final composites to 6.2% and 6.4% for woven and unidirectional kenaf, respectively, compared with 7.9% for non-woven. Because woven kenaf hybrid composite is lightweight, environment friendly, and has a considerable balance in static and fatigue strengths with low fatigue sensitivity in bidirectional planes compared to glass, it is strongly recommended for structural applications.

Effects of the processing method, moisture content, and polymer type were evaluated relative to the physical and mechanical properties of composites based on natural plants. When kenaf was heated above the glass transition temperature of lignin, there was a reduction in moisture content by more than 8% of the total weight of the raw material. To investigate polymer behavior, the raw material was reinforced with three types of polymers: epoxy, unsaturated polyester (UP), and vinyl ester fabricated using hand lay-up with cold press (HCP) and vacuum infusion (VI). The results of (HCP) showed a noticeable improvement in tensile and flexural strength and their moduli for all types of polymer used compared with (VI), in ascending order from UP and vinyl ester to epoxy. Using the HCP method, the tensile strength improved considerably, by 60% for epoxy, 59% for UP, and 250% for vinyl ester, while flexural strength was enhanced by 16% for epoxy, 126% for UP, and 117% for vinyl ester compared to VI. Impact results showed a slight or no improvement in absorbed energy.

The effect of thermal-treatment severity of wood on the mechanical and morphological properties of wood plastic composites (WPCs) was investigated. Wood chips were first heat treated at 120, 150, or 180 ºC for 30 or 120 min under saturated steam in a digester. The composites were composed of thermally treated and untreated wood flour, polypropylene, and a coupling agent, produced by melt compounding and then injection molding. The thermal-treatment of the beech wood improved some mechanical properties of the WPCs, depending on the treatment-time and temperature. The SEM micrographs of the composites showed that the outer surface of the wood fiber was coated by a section of amorphous lignin. The SEM images showed that the WPCs produced from the wood treated at 150 ºC for 30 min had considerably fewer holes and many broken fiber ends embedded in the polymer matrix, indicating better compatibility between the wood flour and the polymer matrix. Based on the results of the mechanical testing of the WPCs, the optimum thermal-treatment for WPC production was 150 °C for 30 min. F

Traditionally, lumber cutting systems in rough mills have either first ripped lumber into wide strips and then crosscut the resulting strips into component lengths (rip-first), or first crosscut the lumber into component lengths, then ripped the segments to the required widths (crosscut-first). Each method has its advantages and disadvantages. Crosscut-first typically works best for the production of wider components, while rip-first favors the production of narrower and longer components. Thus, whichever type of processing method is selected for a given rough mill usually depends on the characteristics of the cutting bills the mill expects to process. There is a third option, a dual-line mill that contains both rip-first and crosscut-first processing streams. To date, such mills have been rare for a variety of reasons, complexity and cost being among them. However, dual-line systems allow the mill to respond to varying cutting bill size demands as well as to board characteristics that favor one method (rip-first or crosscut-first) over the other. Using the Rough Mill Simulator (ROMI 4), this paper examines the yield improvement potential of dual-line processing over single-system processing (i.e., rip-first or crosscut-first processing alone) for a variety of cutting bills and lumber grade mixes.

The synergistic action of water-methanol (1:1 v/v) inner bark extract of barberry (IBEB) stem and biocide, propiconazole (PCZ), and non-biocidal additives, EDTA, BHT, and their combinations with various concentrations (50, 150, 250, 350, and 450 ppm) against the white-rot fungus, Trametes (Coriolus) versicolor was investigated. Results obtained herein demonstrated that IBEB by itself did not exhibit antifungal property, and enhanced protection was further observed by combining it with PCZ. BHT and PCZ showed inhibition percentages of 54.3% and 43.6%, respectively, against the growth of T. versicolor, which reached 75% with BHT at 50 ppm. A synergistic effect was found by introducing PCZ to IBEB when tested against T. versicolor in vitro, with an inhibition percentage of 62% at 150 ppm. No synergistic action was exhibited from the combination treatment of IBEB+EDTA+BHT, and the activity was enhanced by introducing PCZ to this combination treatment (50% at 350 ppm). Significant synergistic action between each of factors of IBEB+PCZ, EDTA+PCZ, and BHT+PCZ was found with inhibition percentages of 49.7%, 48.6%, and 52.7%, respectively. In conclusion, it is advised that IBEB and PCZ be used clinically at the same time.

To investigate epoxidized palm oil’s (EPO) potential as plasticizer for poly(lactic acid) (PLA), its plasticizing effect was compared with commercialized epoxidized soybean oil (ESO). The plasticizers were respectively melt-compounded into PLA at 3, 5, 10, and 15 wt.%. As it was aimed for the blends to be characterized towards packaging appropriate for food products, they were hot-pressed into ~0.3-mm sheets, which is the approximate thickness of clamshell packaging. Fourier transform infrared spectroscopy (FTIR) confirmed the plasticizers’ compatibility with PLA. At similar loadings, EPO was superior in reinforcing elongation at break (EAB), thermal, and barrier properties of PLA. The ductility of PLA was notably improved to 50.0% with addition of 3 wt.% of EPO. From thermogravimetric analysis (TGA), PLA/EPO5 improved PLA’s thermal stability, while all PLA/ESO blends reported reduced thermal stability. From differential scanning calorimetry (DSC), the increase in crystallinity and the shifts in enthalpy of fusions in all plasticized blends denoted facilitation of PLA to form thermally stable α-form crystals. The addition of EPO enabled PLA to become highly impermeable to oxygen, which can extend its potential in packaging extensive range of oxygen sensitive food.

To enhance the decay resistance of bamboo oriented strand board (OSB) products, the strands were dipped in solutions of alkaline copper quat (ACQ) and copper azole (CA) and bonded with phenol formaldehyde resin into two types of OSB panels, i.e., panels with 100% treated strands and those with treated strands only in the face layers. The results indicated that the decay resistance of treated panels was effectively enhanced. The physical and mechanical properties of all treated panels exceeded the requirements specified for category OSB/4 or OSB/3 in the standard LY/T 1580-2010. Statistical data analysis showed that pretreatment with ACQ and CA did not have detrimental effects on the overall physical and mechanical properties of panels at the loading levels investigated in this study. Panels with pretreated strands only in the face layers had strong decay resistance and comparable overall properties as those with 100% treated strands. The results suggest that pretreatment is a promising way to introduce waterborne ACQ and CA to protect bamboo OSB.

The effects of process variables on regenerable antimicrobial finishing of cotton fabric with nitrogen plasma treatment were investigated. Cotton fabric was treated with a mixture of nitrogen and helium plasma, and it was chlorinated with sodium hypochlorite to impart antimicrobial properties. An orthogonal array testing strategy (OATS) was used in the finishing process to determine the optimum treatment conditions. After finishing, the properties of cotton fabric, including concentration of chlorine, tearing strength, and presence of functional groups, were evaluated by ultraviolet spectroscopy (UV), tear testing, and Fourier transform infrared spectroscopy (FTIR). Cotton fabric treated with nitrogen plasma and chlorination effectively blocked microorganism growth. The resistance to Staphylococcus aureus bacteria was regenerable, and nitrogen plasma treatment showed no noticeable influence on the tearing strength of the cotton fabric.