Volume 10 Issue 4

The feasibility of using near-infrared spectroscopy (NIR) to identify wood species was investigated in this study. Case I considers the principal component analysis scores plot of NIR spectra for three wood species. Case II considers whether NIR combined with partial least squares discriminant analyses can be used to identify the three wood species. Three wood species were studied, and each species included five randomly collected wood blocks, 21 samples for each wood block, and 315 total wood samples. In case I, the samples in the PCA analysis were clustered together. In case II, samples in the training set were classified into the correct group, and the accuracy of the test set was up to 90%.

Nanoscale porosity is critical for cellulose reactivity and can be detrimentally affected by wet pressing. The present study evaluated how wet pressing reduced the nanoscale porosity of a set of pulps produced from sugarcane bagasse. The pulps were produced using hydrothermal treatments, followed by either 160 °C alkaline (sodium hydroxide) or 190 °C organosolv (ethanol-water) pulping. Pulping times (20, 40, 60, 80, and 100 min) and applied pressures in the pressing step (21, 43, 64, 85, and 107 MPa) were varied, and the resulting samples had their nanoscale porosity characterized using calorimetric thermoporometry. The lowest applied pressure (21 MPa) collapsed a considerable fraction of the nanoscale porosities. Otherwise, when additional pressure (up to 107 MPa) was applied, a much lower reduction in porosity was observed. The findings indicate that nanoscale porosity of pulps can be separated into compressible and incompressible components.

This article deals with cutting power during the plane milling of thermally treated and untreated silver birch (Betula pendula Roth.) wood. Thermal treatment was carried out at various temperatures of 160, 180, 210, and 240 °C. The cutting power was measured under various milling conditions, such as rake angle of tool (10°, 15°, 20°, 25°, and 30°), cutting speed (20, 40, and 60 m/s), and feed speed (4, 8, and 11 m/min). Thermal treatment had no clear impact on the cutting power. Treated wood at 160 and 180 °C had lower values of cutting power in comparison with untreated wood, while the opposite trend was observed at 210 and 240 °C. The results show that with increasing speed feed, there is an increase in cutting power, while the opposite effect was achieved by changing the cutting speed. The optimum values of cutting power were achieved at a 10° angle and a thermal treatment of 160 °C.

Biomass yield was studied for tall wheatgrass, tall fescue, tall oatgrass, and Miscanthus ´ giganteus per hectare of cultivation, as well as their calorific value and cost of cultivating these biomasses. Chemical analyses were performed on these raw materials to determine their lignin, cellulose, extractives, and ash contents. The analytical results are compared to the chemical constituents found in birch and pine wood. It was found that the grasses examined in this study differed in biomass yield and cost to cultivate (1 ha plot). Tall wheatgrass, tall fescue, tall oatgrass, and Miscanthus leaves had lower levels of lignin compared with wood, but also lower amounts of cellulose. When determining the cellulose content of these biomasses, the amount of inorganic ash that is bound to them must be taken into account.

The yield and kappa number of kraft pulps from tall wheatgrass, tall fescue, tall oatgrass, and Miscanthus were determined after pulping with 0.9% active alkali per 1% lignin content in raw materials. Fibre properties and test papers were also studied to evaluate the usefulness of these plants for papermaking. These results were compared with pulps prepared from birch and pine wood. Kraft pulps from the straws of grasses had yields similar to that of pulp from pine wood and lower kappa numbers than pulps from birch and pine wood. The tested pulps exhibited a favourable number of fibres in 1 g of pulp, and they resulted in papers with clearly differentiated properties from very resistant to rupture dense papers with very low air permeability, to less resistant to breaking more bulky papers.

Corn stalk rind (CSR) was treated with Trametes hirsuta lg-9 and then refined into pulp. The biotreatment resulted in loss of paper strength and brightness, but energy consumption during refining (ECR) was reduced. Meanwhile, multiple linear regression was carried out, for which ECR served as the dependent variable, and the yield and infrared relative absorbance intensities at 3414 cm-1 and 1653 cm-1 of the biotreated CSR served as independent variables. Results showed that the determining parameters of the biotreated CSR may be used to predict the ECR. In this work, delignified corn stalk pith (CSP) was added to aspen alkaline hydrogen peroxide mechanical pulp (APMP). The CSP enhanced the strength properties of the aspen APMP and inhibited yellowing. The biomechanical pulping of CSR has the potential to produce a low-cost green pulp, and the delignified CSP can serve as a pulp additive.

This paper reviews the published and ongoing research work on kenaf/synthetic and Kevlar®/cellulosic fiber-reinforced composite materials. The combination of natural fibers with synthetic fibers in hybrid composites has become increasingly applied in several different fields of technology and engineering. As a result, a better balance between performance and cost is expected to be achieved by 2015, through appropriate material design. This review is intended to provide an outline of the essential outcomes of those hybrid composite materials currently utilized, focusing on processing and mechanical and structural properties.

Contact angle methods are widely used to evaluate the wettability of cellulose-based surfaces and to judge their suitability for different applications. Wettability affects ink receptivity, coating, absorbency, adhesion, and frictional properties. There has been a continuing quest on the part of researchers to quantify the thermodynamic work of adhesion between cellulosic surfaces and various probe liquids and to account for such components of force as the London/van der Waals dispersion force, hydrogen bonding, and acid and base interactions. However, due in part to the rough, porous, and water-swellable nature of cellulosic materials, poor fits between various theories and contact angle data have been observed. Such problems are compounded by inherent weaknesses and challenges of the theoretical approaches that have been employed up to this point. It appears that insufficient consideration has been given to the challenging nature of cellulosic materials from the perspective of attempting to gain accurate information about different contributions to surface free energy. Strong hysteresis effects, with large differences between advancing and receding contact angles, have been overlooked by many researchers in attempting to quantify the work of adhesion. Experimental and conceptual approaches are suggested as potential ways to achieve more reliable and useful results in future wettability studies of cellulosic surfaces.

The chemical industry is being forced to evaluate new strategies for more effective utilization of renewable feedstocks to diminish the use of fossil resources. In this literature review, the integration of both acidic and alkaline pretreatment phases of hardwood and softwood chips with chemical pulping is discussed. Depending on the pretreatment conditions, high-volume sulfur-free fractions with varying chemical compositions can be produced. In case of acidic pretreatments, the major products include carbohydrates (mono-, oligo-, and polysaccharides), whereas under alkaline (i.e., aqueous NaOH) pretreatment conditions, the sulfur-free fractions of aliphatic carboxylic acids, lignin, and extractives are primarily obtained. All these fractions are potentially interesting groups of compounds and can be used in a number of applications. Finally, the effects of pretreatments on pulping are also considered. Although it is believed that there are important advantages to be gained by integrating this type of renewable raw material-based production, in particular, with kraft pulping, sulfur-free pulping methods such as soda-AQ and oxygen/alkali delignification processes are also briefly discussed.

Anaerobic digestion is a well-established biological process for converting biomass in waste streams into a renewable energy source, and it also contributes to the treatment of these waste streams. In this introductory mini-review, some fundamental aspects of anaerobic digestion for use in the pulp and paper industry and other sectors are briefly summarized. The contents include the basics of anaerobic digestion, feedstocks, key process parameters, and typical anaerobic digesters/reactors and their representative manufactures. Fostering the more efficient and widespread commercial use of anaerobic digestion technologies would be a critical strategy to address the issues of energy, the environment, and sustainability.