Volume 9 Issue 4

Cellulosic fiber extracted from a non-woody, monocotyledonous species of palm tree trunk (PTT) was hydrolyzed with different concentrations of FeCl3 in the presence of hydrochloric acid. The dissolution properties of the amorphous region of palm tree cellulosic fiber (PTC) can be enhanced in the presence of Fe3+ cations in acidic medium. The independent variables, including temperature (x1), time (x2), and concentration of metal chloride (FeCl3) catalyst (x3), were optimized using central composite design (CCD). Responses were measured in terms of percentage crystallinity (y1) and yield (y2) of the prepared hydrocellulose. Analysis of variance (ANOVA) showed that temperature was the most influential factor for hydrolyzing the amorphous sections of cellulose. Under optimum conditions, the percentage crystallinity (y1) and yield (y2) were 68.66% and 83.98%, respectively. Scanning electron microscopy (SEM) analysis and X-ray diffraction techniques were used to obtain more information about the surface morphology and crystallinity of the prepared microcrystalline cellulose (MCC). Infrared spectroscopy and thermal analysis were performed to observe the effect of hydrolysis on the finished products. It was concluded that the addition of FeCl3 salt in acid hydrolyzing medium can substantially increase the crystallinity of palm tree trunk cellulose with significant morphological changes to yield microcrystalline cellulose (MCC).

Cross-laminated timber (CLT) is a building system based on the use of massive, multi-layered solid wood panels. Although CLT as a construction system has been successful in Europe, only a handful of CLT projects have been built in the U.S. This manuscript presents the results from qualitative research, carried out with the objective of assessing the market potential and barriers to the adoption of CLT in the U.S. Insights from national and international experts were collected using semi-structured interviews. Topics included perceived benefits and disadvantages of CLT as a construction system, major barriers to its adoption in the U.S., and level of awareness about CLT among the architecture community.

To evaluate the effects of preparation conditions of a ‘green’ soy-based adhesive (SBA), Viscozyme L was employed to hydrolyze the polysaccharides in defatted soy flour (DSF) for preparing SBAs, and plywood bonded by SBAs with Pinus massoniana veneer was then produced. Effects of enzymolysis pH, temperature, time, and additive amount of the Viscozyme L on water-insoluble substances content (WISC) and bonding strength (boiling-water test) of SBAs were investigated. Results showed that bonding strength increased first then decreased as enzymolysis pH and temperature were increased. WISC decreased with increasing pH and decreased first then increased as temperature increased. WISC decreased and bonding strength improved slowly with the increasing time. Bonding strength improved slowly as additive amount of Viscozyme L increased. WISC decreased as the added amount of Viscozyme L increased and then decreased slowly at the added amount of Viscozyme L of about 50 FBG and beyond. SBAs prepared by Viscozyme L action on soy flour slurry decreased WISC and improved bonding strength. The suitable preparation conditions of SBA for plywood are as follows: enzymolysis pH 5.2, temperature 50 oC, and time 20 min, and the additive amount of Viscozyme L depended on the application condition.

The essential oils extracted by hydro-distillation of Pinus roxburghii wood, bark, and needles were analyzed by GC/MS, and their antibacterial and antioxidant activities were evaluated. Twenty-two, thirty-one, and twenty-eight compounds were identified in the essential oils of wood, bark, and needles, respectively. The major chemical constituents of wood’s essential oil were caryophyllene (16.75%), thunbergol (16.29%), 3-carene (14.95%), cembrene (12.08%), α-thujene (10.81%), and terpinolen (7.17%). In bark, they were α-pinene (31.29%) and 3-carene (28.05%), and in needles, they were α-pinene (39%) and 3-carene (33.37%). Almost all of the essential oils were active against human pathogen bacteria, and the essential oils from bark and needles were active against the plant pathogen bacteria Ralstonia solanacearum and Pectobacterium carotovorum. Alternatively, Erwinia amylovora was resistant to all tested oils. The total antioxidant activities (TAA%) of the essential oils from wood (82 ± 2.12%), and bark (85 ± 1.24%) were higher than that of tannic acid (81 ± 1.02%), and the TAA% from the essential oil of needles (50 ± 2.24%) was lower than that of tannic acid.

In this work, surface modifications of oil palm mesocarp fiber were carried out by using superheated steam, alkali, and consecutive superheated steam-alkali treatments, aiming at modification of fiber’s surface for biocomposite applications. The chemical compositions of fiber were modified after treatments as validated by chemical analysis and Fourier transform infrared spectroscopy. The treated fibers under microscopy observation showed relatively clean, rough, and textured surfaces due to the elimination of impurities and hemicellulose. The crystallinity index and thermal stability of treated fibers were relatively higher than that of untreated fiber as determined by X-ray diffraction and thermogravimetric analyses, respectively. A reduction in water absorption of fiber after treatments was also noted. These results indicated those treatments were effective in modifying the chemical compositions and microstructure of fiber. The treatments also increased the crystallinity and thermal stability, as well as reduced the hygroscopicity of fiber. Those treatments could increase the suitability of fiber to be used in the development of biocomposites.

Malaysia has more than 50 species of bamboo, but few that are utilized commercially. In this study, the physical properties of two of the most popular bamboo species in Malaysia, Gigantochloa scortechinii and Bambusa vulgaris,were evaluated. Moisture content (MC) and shrinkage variation at different height sections at both nodal and internodal categories of the bamboo culm were investigated. A comparison between the height sections and between the nodal and internodal categories, as well as between the species, was carried out. Results indicated a trend of decreasing MC along the culm from base to top, though the difference was not statistically significant. It was also observed that radial shrinkage was slightly greater than tangential shrinkage and was much greater than shrinkage in the longitudinal direction. Nodes appeared to have lower MC and a higher percentage of shrinkage compared to internodes. The shrinkage pattern of the two species of bamboo showed a small radial-to-tangential ratio of 1.15:1, which may have contributed to the dimensional stability of bamboo.

The proper parameters of sanding with an abrasive sanding machine are significant to reduce energy consumption and to improve processing efficiency and quality. The influences of grit size (G), feed speed (U), sanding speed (V), and sanding thickness (Ts) on the sanding force (sF), normal force (nF), arithmetic mean deviation of profile (Ra), power consumption (P), and power efficiency (ε) were analyzed by the orthogonal method in this study. Fuzzy synthetic evaluation (FSE) was adopted to evaluate sF, P, and Ra comprehensively and to determine the optimum sanding parameters. For both medium density fiberboard(MDF) andparticle board(PB), G has the greatest impact on Ra. For MDF, Ts and G have great impacts on sF, G is also the significant factor affecting nF, whereas the significant factors affecting P are U and V. For PB, G, U, and Ts have great impacts on sF, while G and Ts are the significant factors for nF. Significant factors for P are V and Ts. For MDF and PB, when the weight vector (sF, Ra) is (0.3, 0.7), the optimum schemes are G80U3m/minV8.04,9.38,10.74m/sTs0.2,0.3mm and G80U3m/minV9.38m/sTs0.2mm, respectively, and when (sF, Ra) is (0.7, 0.3), the optimum schemes are G80U3,3.72m/minV6.69,8.04,9.38m/sTs0.2 mm and G80U3m/minV8.04, 9.38m/sTs0.2 mm, respectively. Additionally, when the weight vector (P, Ra) is (0.3, 0.7) or (0.7, 0.3), the optimum scheme is G100U2.52m/minV5.35m/sTs0.1 mm.

Microwave treatment (MW) was used to improve the sound absorption capacity of Pinus sylvestris var. mongolica wood. The effects of the processing parameters such as MW intensity, processing time, and board thickness on the sound absorption of treated wood were investigated. Microstructure changes of the wood after microwave treatment were observed using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). It was found that the microwave treatment significantly enhanced the sound absorption capacity of the wood in the middle frequencies. The optimum microwave treatment parameters for Pinus sylvestris var. mongolica wood to achieve an improved permeability are: MW intensity of 18 Kw, board thickness of 30 mm, and processing time of 80 s. The maximum sound absorption coefficient of treated wood was 0.51. Micro-voids were formed in treated wood due to the destruction of the pit membranes, the wood ray cells, as well as the damage in the intercellular layer of the longitudinal tracheids. The number of micro-voids ranging from 7427.6 nm to 400 um increased, resulting in the increase in the air permeability and in sound absorption by the treated wood.

In this study, the application of microwave treatment for wood plasticisation and its densification for flooring system purposes is presented. Microwave plasticisation was carried out using a continuous laboratory device at a frequency of 2.45 GHz, and the testing samples made from European beech (Fagus sylvatica L.) wood were plasticised at different power modes (2 kW, 3.5 kW, and 5 kW). Afterwards, the densification (ratio 50%) of pre-treated samples was performed. The surface temperature (Ts) and average moisture content (MC) of the samples were measured after plasticisation. The results showed the influence of the chosen mode on MC decrease and rapid Ts increase. Thus, the densification of testing samples is affected by different initial conditions that occur during the plasticisation process (MC and Ts). The Brinell hardness (HB) of the densified samples increased by about 57% (2 kW), 103% (3.5 kW), and 83% (5 kW), compared with control samples. These results provide a better understanding of microwave plasticisation usability and its potential optimisation and application in the wood flooring industry.

The heat resistance of glued spruce wood was evaluated for different joint types and adhesives. Bending strength, modulus of elasticity, and also fracture evaluation were investigated on glued spruce samples made by the finger-jointed principle. Finger-jointed samples were glued with polyurethane (PUR) and melamine-urea-formaldehyde (MUF) adhesives. Heat loading was realized at temperatures 60, 80, and 110 °C and compared with wood with 20 °C. A static bending test with four-point flexural test was used. Elevated temperature and adhesive type had an important influence on the bending strength. On the other hand, adhesive type had a significant influence on the modulus of elasticity, but elevated temperature had no substantial influence.