Volume 6 Issue 4

The chemical composition of Astragalus armatus contains quite a high amount of extractives in organic solvents (close to 13%), but a low percentage of lignin (around 17%) and an acceptable content of holocellulose (54%). The α-cellulose content is around 35%, and the ash content is around 3%. Using the insight of such data, the soda-anthraquinone cooking of Astragalus armatus produced lignocellulosic fibres. Different cooking temperatures (100, 120, 140, and 160°C) were tested and the delignification duration was 2 h. A yield of about 30% w/w was obtained, and the obtained pulps had a kappa number of 25. Finally, the isolated fibres were used to produce paper samples with a basis weight of 60 g/m2. The structural and mechanical properties of the prepared samples were close to those of other common annual plant-based fibre mats.

When increasing the wood fiber (WF) content in extruded wood fiber/plastic composites (WPC) foams, a good balance between reducing the cost and obtaining good cell morphology should be maintained. This study examines the relationship between WF content and the foam morphology in WPC foams. The role of WF as cell nucleating agent at low concentrations (10 wt.%) was observed, as WPC foam with 10 wt.% WF had lower average cell size and higher cell density than neat HDPE foams. Increasing the WF content further, decreased the average cell size and cell density, and increased the foam density of WPC foams. These results were linked to the rheological properties and crystallization behavior of HDPE and WPC with different WF content.

This article describes a facile method for the preparation of cellulosic catalyst paper: the in situ synthesis of gold nanoparticles (AuNPs) on zinc oxide (ZnO) whiskers, the preferential support for AuNPs, preloaded into a paper matrix. The ZnO paper composites were fabricated using a high-speed and low-cost paper-making technique, and immersed in an aqueous solution of HAuCl4. After drying, fine 5 nm AuNPs were successfully formed on the ZnO whiskers inside the paper matrix. As-prepared AuNPs@ZnO whisker-containing paper (AuNPs@ZnO paper) is similar to ordinary paper products, being flexible, lightweight, and easy to handle. The AuNPs@ZnO paper exhibited a high catalytic efficiency towards the reduction of 4-nitrophenol to 4-aminophenol in aqueous media. Furthermore, the addition of a polyamideamine epichlorohydrin resin provided a wet strength to the AuNPs@ZnO paper, which enables several catalyst recycles with no significant losses in catalytic activity.

Paper sludge and extraction liquor from water prehydrolysis of Eucalyptus chips before pulping are potential raw materials for ethanol production in an integrated forest biorefinery concept. Ethanol production from paper sludge, extraction liquor from water prehydrolysis of Eucalyptus chips, and a mixture of both using separate hydrolysis and fermentation were investigated. The hydrolysate composed of 51.01±0.72 g/L glucose, 30.11±0.09 g/L xylose, and 13.65±0.94 g/L cellobiose, which was obtained by enzymatic saccharification of the mixture at an initial consistency of 6% (w/v, expressed in terms of total carbohydrate mass), was used for ethanol production by yeast SHY07-1 without prior detoxification and nutrient supplementation. A final ethanol concentration of 36.82±0.35 g/L was achieved, corresponding to an ethanol yield of 0.45±0.04 g/g with a fermentation efficiency of 80.71±0.03% and an ethanol productivity of 0.31±0.01 g/(L h). This confirmed the feasibility of co-fermentation of these two materials for bioconversion to ethanol.

In this study, effects of panel density and adhesive ratio on some physical and mechanical properties of peanut (Arachis hypogaea L.) hull particleboards for general purposes were investigated. Panels were manufactured with various densities (0.5, 0.6, 0.7, and 0.8 g/cm3) and adhesive ratios (core layer 8-9% and face layer 10-11%) using urea-formaldehyde (UF) as an adhesive. All panels were tested for some mechanical (internal bond, modulus of elasticity, and modulus of rupture) and physical (water absorption and thickness swelling) properties. Results indicated that increase in the panel density and adhesive ratio, resulted in an improvement in mechanical and physical properties. Only the panels with 0.8g/cm3 density almost met the requirements for the TS-EN 312 Standard for general purposes. Also, the boards having the lower mechanical properties tested in this study can be used as insulating material in buildings because such materials would not be subjected to any mechanical stress.

Stone groundwood (SGW) is a fibrous matter commonly prepared in a high yield process, and mainly used for papermaking applications. In this work, the use of SGW fibers is explored as reinforcing element of polypropylene (PP) composites. Due to its chemical and superficial features, the use of coupling agents is needed for a good adhesion and stress transfer across the fiber-matrix interface. The intrinsic strength of the reinforcement is a key parameter to predict the mechanical properties of the composite and to perform an interface analysis. The main objective of the present work was the determination of the intrinsic tensile strength of stone groundwood fibers. Coupled and non-coupled PP composites from stone groundwood fibers were prepared. The influence of the surface morphology and the quality at interface on the final properties of the composite was analyzed and compared to that of fiberglass PP composites. The intrinsic tensile properties of stone groundwood fibers, as well as the fiber orientation factor and the interfacial shear strength of the current composites were determined.

Several timbers and crop by-products were subjected to an enzymatic treatment to obtain a xylo-oligosaccharides-enriched preparation. The process was performed by means of the commercial endo-β-1,4-xylanase Buzyme 2511®. The enzymatic cocktail was applied onto the raw ground materials with yield up to 5.3 ± 1.0 g/L xylo-oligosaccharides for apple pomace. In order to make the materials more accessible to enzymatic hydrolysis, they were subjected to thermal-alkaline treatment. The biocatalysis process over the thermo-alkaline treated materials yielded xylo-oligosaccharide solutions with the following concentrations (g/l): 1.3 white poplar (Populus alba), 2.9 giant cane (Arundo donax), 3.7 apple pomace (Malus domestica), and 6.5 stalk of grapes (Vitis vinifera). The preparation resulting from biotransformation of grape stalk contained mostly xylo-oligosaccharides (96% w/v) with a small amount of xylose (3% w/v). The same ratio was obtained when pure xylan from birchwood was used as feedstock.

Due to scarcity of cellulosic wood fibers five bamboo species, namely B. tulda, D. hamiltonii, B. balcooa, M. baccifera, and B. arundinacea, and two eucalyptus species, namely E. tereticornis and E. grandis, were grown under North Indian climatic conditions in order to sustain fiber supply through social forestry. After four years of cultivation, these cellulosic raw materials were evaluated for anatomical structures, fibre dimensions, chemical characterization, and pulp and paper making characteristics. B. balcooa and M. baccifera contained higher holocellulose and α-cellulose contents compared to other bamboo species and lower ash contents, indicating that they are likely to pose less problem during chemical recovery. E. grandis contained higher holocellulose, α-cellulose, and lower lignin contents than that of E. tereticornis. Morphologically, bamboo species did not show much difference in fiber dimensions and their derived values. E. grandis showed problems of kink and curl due to longer fiber length than E. tereticornis. Based on pulp yield, brightness, and pulp viscosity B. balcooa, M. baccifera and E. grandis are better options for social forestry among other species.

Soda pulping was performed using kenaf stalk, core, and bast as raw materials. It was observed that all these components could yield good paper characteristics when the resulting pulps were beaten to a freeness of 200 to 300 mL. Soda pulp made from the stalk was comparable to the frond from oil palm in sheet properties, but the latter would require higher beating energy to reach similar freeness as compared to the former.