Research Articles

Antifungal potential of bark crude extracts of Pinus strobus L., Pinus douglasiana Martinez, Pinus caribaea Morelet [var. Hondurensis (scheclauze) W. H. G. Barrett & Golfari] and Pinus leiophylla Schltdl. & Cham, for inhibiting mycelial growth to fungus Trametes versicolor (L. ex Fr.) Pilát was investigated. Pinus bark was extracted through a mixture of acetone-hexane-water 54:44:2 V. Bioassays were performed according to the agar dilution method (petri dish) using concentrations of 0.1, 0.5, and 1.0 mg mL-1 for each of the obtained extracts. All extracts showed some inhibition degree. Crude extracts of P. strobus bark showed the greatest inhibition degree. Antifungal potential of all tested extracts at a concentration of 1.0 mg mL-1 was classified as toxic. Through simple regression models, concentrations were calculated in order to achieve a 50% inhibition (IC50) and the minimal inhibition concentration (MIC). MIC values were 1.58, 1.72, 1.24, and 1.94 mg mL-1 for bark extracts of P. strobus, P. douglasiana, P. caribaea, and P. leiophylla, respectively.

Defects on the surface of solid wood boards directly affect their mechanical properties and product grades. This study investigated the use of near-infrared spectroscopy (NIRS) to detect and classify defects on the surface of solid wood boards. Pinus koraiensis was selected as the raw material. The experiments focused on the ability to use the model to sort defects on the surface of wood into four types, namely live knots, dead knots, cracks, and defect-free. The test data consisted of 360 NIR absorption spectra of the defect samples using a portable NIR spectrometer, with the wavelength range of 900 to 1900 nm. Three pre-processing methods were used to compare the effects of noise elimination in the original absorption spectra. The NIR discrimination models were developed based on partial least squares and discriminant analysis (PLS-DA), least squares support vector machine (LS-SVM), and back-propagation neural network (BPNN) from 900 to approximately 1900 nm. The results demonstrated that the BPNN model exhibited the highest classification accuracy of 97.92% for the model calibration and 97.50% for the prediction set. These results suggest that there is potential for the NIR method to detect defects and differentiate between types of defects on the surface of solid wood boards.

The mechanical properties of poplar scrimber reinforced with glass fiber mesh were investigated. The influence of the different structures and densities were studied with respect to the modulus of rupture (MOR), modulus of elasticity (MOE), and impact toughness (IT). The glass fiber improved the mechanical properties of poplar scrimber. The MOR, MOE, and IT of the scrimber had an obvious dependence on the number of glass fiber layers. When the layers of glass fiber meshes were increased, the MOR, MOE, and IT were increased compared to the control group (scrimber without glass fiber reinforcement). The MOR, MOE, and IT of single-layer glass fiber reinforced scrimber increased a lot compared to the control group. The MOR, MOE, and IT of double-layer glass fiber reinforced scrimber (DGRS) were increased, but the amplitude of the increase was smaller than that of SGRS. Compared to the MOR, MOE, and IT of DGRS, the MOR, MOE, and IT of triple-layer glass fiber reinforced scrimber (TGRS) decreased slightly. When the density was increased, the increasing rate of the MOR, MOE, and IT of the glass fiber reinforced scrimber showed a downward trend, and the glass fiber had better strengthen effects on the scrimber at low density (0.6 g/cm3 and 0.7 g/cm3).

The effect of fiber surface modification by superheated steam (SHS) treatment and fiber content (30 to 50 wt.%) was evaluated relative to the mechanical, morphology, thermal, and water absorption properties of oil palm mesocarp fiber (OPMF)/polypropylene (PP) biocomposites. SHS treatment of OPMF was conducted between 190 and 230 C for 1 h, then the SHS-treated fiber was subjected to melt-blending with PP for biocomposite production. The biocomposite prepared from SHS-OPMF treated at 210 C with 30 wt.% fiber loading resulted in SHS-OPMF/PP biocomposites with a tensile strength of 20.5 MPa, 25% higher than untreated-OPMF/PP biocomposites. A significant reduction of water absorption by 31% and an improved thermal stability by 8% at T5%degradation were also recorded. Scanning electron microscopy images of fractured SHS-OPMF/PP biocomposites exhibited less fiber pull-out, indicating that SHS treatment improved interfacial adhesion between fiber and PP. The results demonstrated SHS treatment is an effective surface modification method for biocomposite production.

This paper explores changes in the quality of the surface of aspen wood after pressing. Pressing, a type of processing, facilitates changes in surface quality and smoothness, thereby producing wood suitable for the furniture industry. The results obtained for the pressed wood surface were compared with those obtained for wood surfaces that were not subjected to pressing. Attention was paid to the impact of moisture, the degree of compression, and plasticizing by steam. The change in smoothness/ roughness was monitored in both the longitudinal and transverse directions (relative to the grain). The contact method was used to measure the roughness both before and after pressing. The independent variables of moisture content and degree of compression had the greatest impact on the smoothness/roughness. Plasticizing by steam had no greater impact. Therefore, the non-plasticized aspen wood was determined to be more suitable for the given purpose.

This work investigated the impact of dimethyl sulfoxide (DMSO) treatment in the isolation of nanofibrillated cellulose (NFC) from corn husk by the 2,2,6,6,-tetramethylpilperidine-1-oxyl (TEMPO) oxidation method. NFC-A and NFC-B were prepared without and with DMSO treatment before TEMPO oxidation. The extracted NFC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), zeta potential analyzer, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the dimension of both NFC-A and NFC-B were in nanoscale. The crystalline type of NFC was cellulose I, and the crystallinity of NFC was obviously increased. The thermal stability of NFC was reduced slightly. Compared with NFC-A, NFC-B had a narrower distribution range, higher crystallinity, and better thermal stability. This result demonstrated that DMSO treatment did not change the chemical structure of NFC, but it affected their dimension and distribution and improved their dispersion stability, crystallinity, and thermal stability.

A multistage process was employed to obtain value-added products from brewer’s spent grain (BSG). This paper is focused on the production and characterisation of cellulose nano-fibres (CNF) as one of the products obtained during the complete process. In the first stage, protein-rich liquor was separated via the alkaline (NaOH) treatment of dried BSG and stored for further utilisation. In the second stage, bleaching treatments were conducted to separate cellulose, which was later converted to CNF by high-pressure homogenisation. The lignocellulosic product from each step was analysed for its chemical composition by means of alkaline hydrolysis combined with the HPEAC method. The thermal properties were measured using thermogravimetric analysis (TGA). The morphology was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray diffraction (XRD) was done to observe changes in crystallinity. The nano-cellulose produced can be regarded as a value-added material from the bio-refinery of BSG along with numerous already-reported products.