Volume 10 Issue 4

The pyrolysis of waste newspaper (WP) and co-pyrolysis of waste newspaper with high-density polyethylene (HDPE) (1:1 wt%) were carried out in a quartz tube at 500 °C to obtain biochars. The biochars were characterized in detail by X-ray diffraction (XRD), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), elemental analysis, scanning electron microscopy (SEM), automated specific surface area and pore size analyzer, and Raman spectroscopy to determine their physical and chemical properties. The analysis results for WP/HDPE-derived biochar (CWH) were compared to WP-derived biochar (CWB). The CWH had lower oxygen-containing groups, increased aromatic structure, higher calorific value, higher fuel ratio, and greater porosity development. CWH is more appropriate as solid fuel, soil adsorbent, or activated carbon precursor as compared to CWB.

In the present study, oil palm empty fruit bunch (OPEFB) fibers were taken from a 25-year-old oil palm tree. The cellulosic nanofiber (CNF) was isolated from the OPEFB using a chemo-mechanical process and utilized as reinforcement in an epoxy matrix. Various CNF loading percentages (0 to 0.75%) were applied in the epoxy matrix to explore the potential of using OPEFB-CNF as reinforcement. The morphological, mechanical, physical, and thermal characteristics of the OPEFB nanofiber-reinforced epoxy composites were evaluated. Results showed that the 0.25% and 0.5% CNF loadings were homogenously distributed and well-dispersed in the composite matrix. Conversely, agglomeration was detected in the matrix with 0.75% CNF loading. Determination of the water absorption behavior of CNF-reinforced epoxy composites at various loadings revealed that the physical properties of the composites increased with reinforcement loading. Furthermore, the analyses of the mechanical and thermal properties of the CNF-reinforced composites revealed that the incorporation of OPEFB-CNF enhanced the mechanical performance and thermal stability up to 0.5% loading.

This paper investigates the effect of heat treatment temperature on the stiffness and strength properties of Douglas fir (Pseudotsuga menziesii Franco) and common alder (Alnus glutinosa Gaertn.) woods. Two temperatures of heat treatment were used: 165 and 210 °C. The effects of dynamic elasticity modulus, static elasticity modulus, impact toughness, bending strength, and density were evaluated. It is already understood that the mechanical properties, primarily the bending strength, decreases with increasing temperature. In contrast to the favorable stability in shape and dimension that was achieved, the changes in the woods’ properties with temperature were mostly negative. Higher heat treatment temperatures corresponded with lower stiffness and strength properties. For higher temperature treatments, above 200 °C, deterioration of the tested properties was noticable as a result of the significant changes in the wood chemical structure. Even the positive effect of the equilibrium moisture decrease was not able to counterbalance the unfavorable changes. Moreover, it was observed that as the hemicellulose content is higher in alder wood, density, static bending strength, and toughness all decreased steadily at high temperatures, compared to Douglas fir wood.

Zinc-aluminium layered double oxide (Zn-Al-LDO) catalysts derived from layered double hydroxides (LDHs) were prepared and used for the catalytic fast pyrolysis of cellulose to selectively produce 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one (LAC), which is a valuable anhydrosugar derivative. Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to investigate the LAC production under different reaction conditions. The results indicated that the Zn-Al-LDO catalysts were capable of greatly inhibiting the pyrolytic formation of levoglucosan (LG) and capable of promoting the formation of LAC and certain other products. The catalyst with the Zn/Al molar ratio of 2 exhibited the best catalytic capacity for LAC production. Both pyrolysis temperature and the catalyst-to-cellulose ratio affected the pyrolytic product distribution remarkably. The maximal LAC yield was obtained at the pyrolysis temperature of 350 °C and catalyst-to-cellulose ratio of 4 and featured a peak area percentage of 21.9% (calculated by GC/MS), compared with only 3.0% from the non-catalytic process. In addition, the LDO catalyst performed better than the previously reported montmorillonite K-10 catalyst on the enhancement of LAC production.

The ability to increase the filler content of paper without significantly sacrificing its mechanical strength is of high interest for papermakers. In this work, three samples of ground calcium carbonate (GCC), differing in size and in brightness, modified with silica via the sol-gel method, were used as fillers in papermaking. Handsheets were produced using a eucalyptus kraft pulp furnish and with a filler amount near 20%. It was found that not only were the strength properties of the handsheets produced with the modified GCCs always significantly better than those obtained with the unmodified GCCs (e.g., the tensile index exhibited improvements of 16 to 20%), but bulk also was increased (by 7 to 13%). Some decreases in the light scattering and opacity values were noted when using the modified GCC, but the brightness was roughly the same. The enhanced fiber-to-filler bonding may be attributed to the hydrogen bonding between the cellulosic fibers and the hydroxyl groups of the silica coating the calcium carbonate particles.

Reducing the consumption of phenol during synthesis of phenolic resins is of great technological and scientific interest because of its economic and environmental implications. In this work, the use of hydroxymethylated lignins as a partial replacement for phenol in resol phenol-formaldehyde resins used for the production of decorative laminates was experimentally studied. The work involved: i) the industrial synthesis of traditional and modified resols with 10%w/w of sodium lignosulfonate and kraft-type lignin; ii) the industrial impregnation of kraft-type paper with the produced resins; iii) the production of laminates on both laboratory and industrial scales; and iv) the measurement of their final properties. The mechanical performance of the laminates was evaluated via the determination of the Young modulus, bending strength, biaxial impact strength, and Mode-I interlaminar fracture toughness. The (modified and traditional) laminates exhibited statistically significant differences in mechanical properties. However, the partial lignin replacement did not produce effects that were detrimental to the overall performance of the decorative laminates.

A novel crosslinked hydrogel was prepared from sodium carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) using ammonium persulfate as an initiator and methylenebisacrylamide as a crosslinker for drug delivery. The chemical structure of the copolymer was characterized by Fourier transform infrared spectroscopy and X-ray diffraction, and the morphology was observed under scanning electron microscopy. The swelling behavior of the hydrogels confirmed the pH- and ionic strength-sensitivity. The reversibility of the hydrogels and the on-off switching behavior were also investigated, providing the potential for drug delivery. The release of bovine serum albumin (BSA) from drug-loaded hydrogels was studied at different pH conditions to simulate gastrointestinal conditions. The amount of BSA released from the hydrogels at pH 1.2 was relatively low (17.8%), while 85.2% was released at pH 7.4. According to the results, the CMC/HEC hydrogel has the potential for use in the controlled release of oral medication.

(NH4)2SO4 solution was employed to pre-treat regenerated cellulose fiber (from bamboo) using an ultrasonic method, and then the material was heat-treated at 250 °C. Scanning electron microscopy revealed that erosion and cracks of the fiber surface increased after being impregnated with (NH4)2SO4 combined with ultrasonic pretreatment. There was a small change in the intensity and the position of some peaks in the Fourier transform infrared spectra, and in the heat treatment, partial pyrolysis of the cellulose occurred. The data showed that for the cellulose fiber pretreated with 5 wt% (NH4)2SO4 the decomposition temperature shifted to the lower side (252 °C), and the decomposition range (180 °C to 454 °C) was wider than for the other impregnation fibers and reference. However, the rate of decomposition was different with different concentrations of (NH4)2SO4. The C content of heat-treated fiber with 5 wt% (NH4)2SO4 increased to 52%. The above results indicated that the (NH4)2SO4 was an effective catalyst to pretreat regenerated cellulose fiber in the pathway of pyrolysis.

This work focuses on the mechanical properties and solid particle impact behaviour of Luffa cylindrica fibre (LCF)-reinforced epoxy composites. Single (SL)-, double (DL)-, and triple (TL)-layered composites were prepared using the general hand lay-up technique. The erosive wear test was carried out using an air jet erosion tester according to the ASTM G76 standard. The erodent used was silica sand particles (200 ± 50 µm). The experimental parameters studied for the erosion rate of the LCF epoxy composites were impingement angle (30° to 90°) and particle velocity (48 m/s to 82 m/s). Analysis of the results revealed that at the peak erosion rate, semi ductile behaviour of the composite was apparent. Possible erosion mechanisms were discussed and were investigated using scanning electron microscopy (SEM).

Wood is a pure, sustainable, renewable material. The increasing use of wood for construction can improve its sustainability. There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. However, comparative market and economy studies are still scarce. In this study, the following assembling techniques were compared: laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. The production costs, durability, and ecological considerations were presented. This study was based on reviews of published works and information gathered from 27 leading wood product manufacturing companies in six European countries. The study shows that the various techniques of assembling multi-layer wooden construction panel elements are very different. Cross laminated timber (CLT) exhibited the best results in terms of cost and durability. With regard to ecological concerns, dovetailing is the best. Taking into account both durability and ecological considerations, doweling is the best. These alternatives give manufacturers some freedom of choice regarding the visibility of surfaces and the efficient use of lower-quality timber. CLT is the most cost-effective, is not patented, and is a well-established option on the market today.