Volume 15 Issue 3

Many words have been written regarding alkaline sizing of paper. The learned works often launch directly into cellulose-size reactions. Starch – a carbohydrate with a similar surface chemistry to cellulose – rarely features in the considerations. Yet the contact of size with the starch may be far more intimate and extensive than the contact with cellulose. It is suggested that the reaction of the size with starch is an important and overlooked contribution to our understanding of sizing.

The outbreak of coronavirus disease 2019 (COVID-19) has made a huge impact on the global industrial supply chains. Undoubtedly, COVID-19 is posing severe challenges to the pulp and paper industry worldwide. On the other hand, this pandemic may provide unprecedented possibilities for the pulp and paper manufacturers in areas such as the increasing demand for personal hygiene paper products, food packaging products, corrugated packaging materials, medical specialty papers, etc.

Wood-based mass-panels (WBMP) are emerging as an attractive construction product for large-scale residential and commercial construction. Australia is following the lead of Europe and North America with several recent projects being completed using predominately cross-laminated timber panels (CLT). These sawn timber-based panels offer some key advantages to the construction and sawmilling industry. However, veneer-based mass-panel (VBMP) systems could offer additional benefits including the more efficient use of the available forest resources to produce WBMPs that have equivalent to superior performance to CLT. Research to confirm the expected technical viability of veneer-based systems is required. VBMPs could provide a valuable contribution, alongside CLT, to the Australian timber products market.

The dominating role of colloid science in papermaking processes, as exemplified by wet-end chemistry, is now well known. The concept of colloids dates back to about 160 years ago. In certain cases, however, the term “colloids” can have an overlapping meaning with the modern terms “nanomaterials” and “supramolecular assemblies”. The latter terms, and the scientists who have gravitated to those terms, have enriched colloid science, providing new insights into colloidal systems. It is proposed here that reconsidering papermaking in light of these multi-disciplinary sciences has potential to facilitate effective teaching and learning pertaining to universities that have pulp and paper programs. Enhanced integration of basic sciences with papermaking may further our understanding and broaden existing research areas, which is likely to create breakthroughs in basic research, applied research, and product development.

Air pollution poses a great threat to human health, and it has become a worldwide problem that needs to be urgently dealt with. Many measures have been taken to reduce air pollution and improve air quality. These methods are generally costly and require special equipment. Some plants have the ability to assimilate, degrade, or modify toxic pollutants in air into less toxic ones. It is proposed here to develop plant-based technology to clean polluted air at low cost. This air phytoremediation technology has many potential advantages in contrast with traditional air pollution treatment methods. It is simple, potentially cheap, and easily implemented. Plants to be used for air phytoremediation have the potential to reduce pollutants in air and improve air quality; they also fix carbon dioxide through photosynthesis and help to decrease greenhouse gases in the atmosphere. The selected plants can also be used as raw materials for production of energy and bio-based chemicals. However, little research has been carried out on air phytoremediation technology, especially in the basic research area. This editorial gives a brief discussion about air phytoremediation to stimulate more research on this technology and further improve its effectiveness in practical use.

Blended species plywood blocks comprising of 24 different veneer configurations of naturally durable white cypress pine and non-durable hoop pine were exposed to the subterranean termite Coptotermes acinaciformis in a field trial in Australia. Three thicknesses of cypress (1.8, 2.8, and 3.0 mm) and hoop pine (1.0, 1.5, and 3.0 mm) veneer were included. Blocks were assessed for termite damage using a visual damage rating and mass loss measurement. Blocks using all hoop pine veneers received substantial damage; however, blocks that had cypress face and back veneers had improved termite resistance, particularly for the 1.0-mm hoop pine core veneers. When cypress longbands were blended with hoop pine crossbands that created alternating layers, minimal damage was sustained in the hoop pine veneers; however, the damage increased with increasing hoop pine veneer thickness. All cypress veneers received essentially no termite damage, and cypress veneer thickness did not influence the severity of hoop pine veneer damage. The trial indicated that the plywood made with hoop pine core veneers, cypress pine face, and back veneers offered some termite resistance if the hoop pine veneer thickness was kept thin. Alternating cypress and hoop pine further improved the termite resistance.

To explore the properties of wood-plastic composites (WPCs) used in maritime climates, four different plant fibers (bamboo, rice straw, wheat straw, reed straw), and polyvinyl chloride (PVC) were used to prepare WPCs through extrusion. The composites were subjected to either seawater immersion + xenon lamp aging or deionized water spray + xenon lamp aging. The mechanical properties (tensile strength, flexural strength, impact strength), color change, and water absorption performance were analyzed. The plant fibers were analyzed by X-ray diffraction and Fourier transform infrared spectroscopy (FTIR), and the microstructures of the surfaces were observed by scanning electron microscopy (SEM). The reed fiber had the highest crystallinity; reed/PVC composites had good interface with the plastic matrix, less internal defects, and the best comprehensive performance, with a tensile strength, bending strength, and impact strength of 25.4 MPa, 34.4 MPa, and 4.30 KJ·m-2, respectively. The simulated seawater immersion + xenon lamp aging reduced the performance of wood-plastic composites, destroyed the quality of the combination of plant fibers and plastic matrix, and created internal defects. The comprehensive mechanical properties of reed/PVC composites were the best. The properties of bamboo/PVC composites decreased the least, with a decrease of less than 41.2%.

Lignin-containing nanofibrillated cellulose (LNFC) were prepared from p-toluenesulfonic acid (p-TsOH) pretreated sugarcane bagasse (SCB) using either formic acid (FA) or hydrochloric acid (HCl) and high-pressure homogenization. The composition, morphology, dispersity, crystallinity, particle size, thermal stability, and hydrophobicity of LNFC treated with FA (F- LNFC) and HCl (H- LNFC) were compared via electron microscopy, an X-ray diffractometer (XRD), a thermal gravimetric analyzer (TGA), a Fourier transform infrared spectroscope (FTIR), and water contact angle (WCA) analysis. The results of morphology and dispersity testing showed that LNFC with uniform dispersion were successfully prepared using a homogeneous pressure of 30 MPa and the F- LNFC particles were more stable in an aqueous solution. The crystallinity of the LNFC was well maintained after homogenization. The TGA, FTIR, and WCA data indicated that F-LNFC had better thermal stability and were more hydrophobic than H-LNFC because FA could esterify cellulose. Improved dispersity and thermal stability and increased crystallinity and hydrophobicity of cellulose nanofibrils would enhance the performance of nanocomposite materials.

Regenerated cellulose film (RCF) has potential as a conductive substrate due to features such as its degradability, transparency, and flexibility. Indium doped tin oxide (ITO) is a conventional conductive material, but its rigidity restricts the formation of flexible conductive film. In this study, silver nanowires (AgNWs) were introduced between the RCF and the ITO conductive framework. Additionally, the fabrication of flexible, conductive, and transparent RCF was conducted. The AgNWs-ITO based RCF demonstrated high conductivity (170 Ω per sq) and transparency (78%) by the addition of 50 μL of AgNWs. After bending the sample 50 times with a 5 mm curve radius, the as-prepared conductive RCF presented an electric resistance improvement of 19%, with a 485% increase for the control ITO-based RCF. This is a result of the AgNWs framework, which can lessen the destruction of the bending treatment on the conductive layer and can also desirably connect the ITO conductive sections. The novel approach can expedite the versatile applications of flexibly conductive RCF on printable, portable, and wearable electronic devices.

Inhomogeneities in wood and wood products are evident. Sometimes these inhomogeneities are combined with other inhomogeneities such as drilling. Each can have different effects on dynamic properties, and these footprints can cause hidden defects in wood and wood products. In this research, the effects of artificial inhomogeneity of density and drilling diameters (1 mm, 3 mm, 5 mm, and 10 mm) on dynamic properties of the beams produced from oak wood jointed with poplar blocks (one at the end and the other at the central part of the beam) were investigated. Free vibration on a free-free beam test was subjected for the evaluations. The results indicated that factors such as dynamic modulus of elasticity, acoustic coefficients, and damping capacity, were affected by both inhomogeneity and drillings. The acoustical converting efficiency showed the exact location of inhomogeneity. It also showed the level of drilling diameter.