Research Articles

Chemical, physical, and barrier properties of flaxseed mucilage-based films were investigated to determine the appropriate applications for coating or packaging of food or bioproducts. The film samples were formed via casting with the addition of glycerol as a plasticizer up to a maximum of 5 wt.%. Fourier transform infrared (FTIR) spectra showed an increase of intensity in the –OH stretching vibration region and the appearance of a new peak at 2883.1 cm^-1 in the plasticized film samples. These changes may indicate possible interactions between the mucilage and glycerol. With increasing glycerol concentration, the water activity decreased, while the moisture content and water solubility increased. With regard to barrier properties, the water vapour permeability (WVP) and oxygen permeability (OP) notably increased with increasing glycerol content. With these high WVP and OP values, the films can be potentially extended for coating or packaging fresh produce.

The thermal, flammability, and morphological properties were investigated for a nano-composite made from fir wood flour and polypropylene. Polypropylene (PP), fir wood flour, maleic anhydride polypropylene (MAPP), and nanosilica at 5 different concentrations (0, 2, 4, 6, and 8 phc), were mixed using an extruder, and samples were made using a hand-press. Then, the hardness and the thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limited oxygen index (LOI), X-ray diffraction (XRD), and scanning electron microscopy (SEM) results were studied. The results showed that increasing the nanosilica content up to 8 phc increased the hardness. Also, when the nanosilica content was increased to 8 phc, the thermal stability increased and more charcoal was retained. Increasing the nanosilica content increased the crystallization. The limited oxygen index increased. Studying the x-ray diffraction spectrum showed that the width and peak intensity decreased with the increased intake of silica nanoparticles. Scanning electron microscopy images showed that an increased concentration of nanosilica meant better connections and a more uniform bond was established between the fibers and the matrix.

The palm kernel cake (PKC) inclusion level in poultry diets is limited by the high indigestible polysaccharides content. Hence, PKC was subjected to an extrusion treatment to reduce the content of these components. The effects of extrusion on the total non-starch polysaccharides (T-NSP), fibre, monosaccharides, and mannooligosaccharides contents were evaluated according to the response surface methodology (RSM) with various temperatures, screw speeds, hopper speeds, and moisture contents. The optimum conditions observed according to the RSM were a temperature of 178 °C, screw speed of 100 rpm, hopper speed of 5 Hz, and moisture content of 75%. The T-NSP content was significantly reduced (p<0.05), from 63.3 ± 1.85% to 57.6 ± 0.89%, and the crude fibre content decreased (p<0.05) from 16.7 ± 0.68% to 13.5 ± 0.99%. The mannose, glucose, and fructose contents of the PKC increased (p<0.05) 2.9-, 1.9-, and 1.4-fold, respectively. The 1,4-β-D-mannobiose, 1,4-β-D-mannotriose, 1,4-β-D-mannotetraose, and 1,4-β-D-mannopentaose increased (p<0.05) 3.7-, 3.8-, 3.5-, and 32.8-fold, respectively. This study showed that extrusion enhanced the nutritive value of PKC.

Binderless particleboards of Phoenix canariensis were manufactured by hot pressing at a low temperature (120 °C) and low pressure (2.6 MPa). Nine different configurations were analyzed to study different palm tissues. The experimental panels were tested for their mechanical and physical properties according to the procedures defined by the European Union (EN) standards. The microstructure of the raw material was investigated by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector for microanalysis (EDXA). The physical and mechanical behavior seemed to be influenced by the amount of parenchymatous tissue. Raw material and particle size have a profound effect on the board properties. The mechanism of self-bonding could have resulted from the high content of sugars, which were partly transformed into furfural. The use of this waste material could be beneficial to the environment because it is a method of carbon fixation, helping to decrease atmospheric CO2.

In this short communication, UV/Vis spectrophotometry is described as an analytical tool for the quantification of lignin content in deep eutectic solutions. The lignin was solubilized with different deep eutectic solvent (DES). DESs were prepared as binary mixtures of choline chloride with lactic acid (1:9); (1:10); ethylene glycol (1:2); glycerol (1:2) and alanine:lactic acid (1:9), and betaine:lactic acid (1:2). The UV-Vis spectrometric quantification of the solubilized lignins was independent of the type of solubilized lignin. The approach consists of measuring the absorbance of a solution of lignins dissolved in the deep eutectic solvents at an absorbance of 440 nm.

This study aimed to evaluate the yield and efficiency of lignin extraction from Eucalyptus grandis × Eucalyptus urophylla wood chips from treatments with sodium xylenesulphonate (SXS), and to determine their optimum conditions. First the wood’s physical, chemical, and morphological properties were characterized. Then, the wood chips underwent treatments from a combination of the following factors: time, SXS concentration, and temperature. For each treatment the yield and lignin content remaining in wood chips was determined, from which optimum points were obtained for maximum yield and lignin extraction. The physical, chemical, and morphological characterization showed that the concerned wood showed values in line with those cited in previous literature. Treatments with SXS were efficient in lignin extraction. The treatment that provided the highest calculated yield of wood was 1 h, 0%, 117.5 ºC; and the greatest lignin extraction was with 12 h, 30%, 130 ºC, removing 39.6% of lignin from wood chips. In general, the treatment of E. grandis × E. urophylla wood chips with SXS was effective in extracting lignin. However, the calculated yield and lignin extraction showed antagonistic behaviors; therefore, in light of the objectives, a careful assessment is required when using this treatment on an industrial scale to seek a balance point between the two parameters.

Wood flour-poly(lactic acid) 3D printing filaments were prepared via a melt extrusion method. Poplar wood flour and poly(lactic acid) (PLA) were used as raw materials, and different combinations of glycerol and tributyl citrate (TBC) (4% glycerol, 2% glycerol + 2% TBC, 4% TBC) were used as plasticizers. A 3D printer was used to print the filaments into standard test specimens with dimensions of 150 mm × 10 mm × 0.2 mm at the printing temperature of 220 °C. The performance of wood flour-poly(lactic acid) 3D printing filaments in terms of their interfacial compatibility, mechanical properties, melt index (MI), water absorption, and heat stability was tested under different plasticizer combinations. The results showed that under the condition of same dosage of plasticizer, the order of MI for the 3D printed filaments from high to low was 4% glycerol > 2% glycerol + 2% TBC > 4% TBC, which indicated that glycerol was more favorable for the extrusion processing of the composite filaments. However, in terms of compatibility, mechanical properties, water absorption, and thermal stability, the 3D printing filaments with 4% TBC showed better performance compared with other groups.

The demand has grown in many fields for materials that are eco-friendly and sustainably developed. In this study, several formulations of novel wood fiber reinforced ultra-high-density fiberboards (UHDFs) using resol-type phenolic resin (RTPR) as binders were manufactured for application in decorative building facades. The influences of the various formulations on water resistance and the mechanical, thermal, and fire-resistant properties were systematically examined. All formulations of the UHDFs exhibited better water resistance, internal bonding, and fire resistance as the RTPR content and density increased. To better evaluate mechanical properties, the microstructure of the UHDFs was observed using scanning electron microscopy. After optimization of hot-pressing conditions, UHDFs with excellent mechanical properties of approximately 7.2 GPa, 85.9 MPa, and 5.4 MPa for bending modulus, bending strength, and internal bonding, respectively, were achieved. Good water and flame resistance were also achieved, which makes these materials competitive with other commercial products.

Biochars are considered as promising sorbents for the removal of aqueous metal ions. The aim of this study was to explore the adsorption mechanisms through the integrated characterization of the pristine and Pb(II)-loaded biochars derived from herbaceous plant, biosolid, and livestock waste with different physicochemical properties. The biochar derived from livestock waste exhibited higher Pb sorption capacity than the others. Experimental data of sorption kinetics and isotherms were well fitted by kinetic models and Langmuir isotherm model, respectively. Comparisons of Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) between the pre- and post-adsorption biochars revealed the formation of Pb-carbonate, suggesting that the surface precipitation was the dominant adsorption mechanism. The combination of multiple characterizations and batch adsorption can make further exploration on the adsorption mechanism of Pb(II) adsorption onto the resultant biochars.

Cellulose nanowhiskers (CNW) were successfully isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) through sulfuric acid (H₂SO₄) hydrolysis with different reaction times. OPEFB-MCC was hydrolyzed with 64 wt.% H₂SO₄ at 40 °C and various reaction times (30, 60, and 90 min). Effects of the hydrolysis time on the morphologies and properties of the cellulose were evaluated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). The FTIR analysis showed that the chemical compositions of all of the samples were the same and represented the cellulose I structure. Hydrolysis time had little effect on the crystallinity index of the CNW, as was revealed by the XRD. The TEM images showed that the CNW produced with different reaction times had a rod-like shape and similar diameters and lengths. The produced CNW had better thermal stabilities than the OPEFB-MCC.