Volume 17 Issue 3

Thermoplastics are an important class of polymers that find widespread use in a broad variety of applications. Because of environmental concerns regarding the lack of biodegradability of synthetic thermoplastics, green alternatives are increasingly studied that should be both based on renewable resources and biodegradable. In this regard, polysaccharide esters of naturally occurring fatty acids are in the center of interest.

People often think of paper as an environmentally harmful product because trees are cut down to make it. A new generation that has grown up in today’s digital society may think that the use of digital devices is a waste-free way to protect our environment. Although the pulp and paper industry is making various efforts to preserve the environment, it has not been properly recognized. Developing new technologies to produce better products at lower cost while protecting our environment is important. But it is also important to enhance the image of the pulp and paper industry in the eyes of the public. The pulp and paper industry’s efforts to reforestation for raw materials and to expand the recycling of waste paper should be more widely introduced.

The concept of mimetics can be defined in terms of “learning from others” or “inspired by others”, and indeed its essence is “universal”. A well-known marvelous example of designing materials inspired by nature is human flight. Essentially, everything can be mimicked somehow in this huge world. In this sense, the characteristics of polysaccharides, including chitosan, can shed light on new product development. Owing to the interesting features of chitosan, such as nontoxicity, biodegradability, antibacterial activity, and the puzzling hydrophobic nature of chitosan films, the synthesis of chitosan-mimetic materials represents a promising strategy for developing a diverse group of functional products. The abundant amino and hydroxyl groups of chitosan are the basis for designing different functional materials. It is expected that chitosan-mimetic strategies may potentially address issues or challenges related to the commercial use of chitosan. For example, chitosan functions well as a paper additive (e.g. surface sizing); however, its use is strongly hampered by high cost, poor water-solubility, etc. In this case, chitosan-mimetic products derived from low-cost materials (e.g., starch) may be considered as alternatives to chitosan. Limitless types of products stemming from the interaction between mimetics and chitosan are designable, potentially creating endless opportunities for different industrial sectors.

Recent years of research and development have brought frequently used terms for new types of green solvents to the lexicon of scientists. This can lead to terminological inaccuracies. In particular, different names are being used for the same types of solvents: Deep Eutectic Solvents (DES); Natural Deep Eutectic Solvents; Low-Transition Temperature Mixtures; Low-Melting Mixtures. It would, therefore, be appropriate to eliminate certain inaccuracies and to use simplification, which means using the general term “Low-Temperature Transition Mixtures” or introducing the term “DES-like mixtures”.

A physical coagulator of fines was employed to separate suspensions comprising refined sulphate cellulose and waste paper, where no reagents were required. The physical coagulator was a porous cylinder with a rotating disk placed in its cavity. Using the MorFi Neo fibre analyser and the Hitachi SU 3500 digital microscope, a dispersed size distribution of well-developed fines in a suspension derived from softwood and hardwood pulp was obtained. The kinetics of fine sedimentation in the suspension was studied. The sedimentation rate of both individual agglomerates and a mass of them, as well as the magnitude of mass concentration in a cleared liquid, was determined. A relationship between the concentration of fines in the suspension and the structure of the pulp during their sedimentation was established. To intensify the fines sedimentation process, it was proposed to return a part of the sediment to the suspension passing into the physical coagulator. Process parameters for the sedimentation process and the construction of the sedimentation tank were obtained. The unit designed for collecting fines from the suspension is shown schematically. Use of this unit reduced the fibre sedimentation time, decreased the loads in wastewaters, and retained the consumer value of the pulp fibres.

In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulus of elasticity (EM) in static bending from specimens measuring 5 cm × 5 cm × 115 cm. Thus, the relationship between the test span (L) and the specimen height (h) greater than or equal to 21 (L/h ≥ 21) is respected, ensuring that the effect of shear in the calculation of displacements is negligible (Euler Bernoulli Theory). Considering the expressive number of tree species cataloged in the Brazilian Amazon Forest, any procedure that aims to facilitate the realization of experimental tests is highly desirable because it provides the knowledge of unusual species. These wood species may potentially replace woods that have been traditionally used and historically exploited. Using five hardwood species, this research aimed to verify, while maintaining constant L/h ≥ 21 ratios, the influence of specimens dimensions in the determination of fM and EM. For all species studied, the statistical analysis found equivalence in the values of fM and EM determined as a function of the sample sizes. Therefore, respecting the ratio L/h ≥ 21, the size of the specimens does not influence the determination of strength and stiffness in static bending.

To solve the problem of pure perceptual and non-standardized selection of colour in furniture, a rational and reliable colour quantitative system was developed. This approach is beneficial to the upgrading and optimization of products by furniture manufacturing enterprises. The wardrobe colour selection system is based on the Munsell colour system, the colour harmony theory and the Birkhoff aesthetic colour selection system to construct a wardrobe colour selection system. It has three analytical parts, consisting of wardrobe colour selection and data analysis, which can provide a reference for the colour quantification used by furniture enterprises. Once the system was constructed, a company’s wardrobe colour selection and coated sheet sample was used as an example to test its efficacy. The wardrobe colour selection system was evaluated to optimize the design of the company’s original wardrobe product colour selection. The results showed that the wardrobe colour selection system improved consumers’ preference for the company’s wardrobe colour selection. The wardrobe colour selection system provides a reference for furniture companies, engineers and designers in product colour selection and optimization design, which is conducive to scientifically informed manufacture and a standard formulation of furniture colour.

Black spruce is widely used for lumber production in Eastern Canada, and it has the potential to replace trembling aspen and paper birch for oriented strand board (OSB) manufacturing. This study evaluated the bending modulus of elasticity (MOE) and modulus of rupture (MOR), the internal bond (IB), and the thickness swelling (TS) of OSB panels made from black spruce and trembling aspen strands and how they were affected by strand geometry. All the panels met the CSA O437 (1993) standard for class O-2 properties except for the TS. The strand thickness had a significantly negative effect on the bending properties but a significantly positive effect on the IB and TS properties. The strand length had a significantly positive effect on the parallel bending properties but a significantly negative effect on the perpendicular bending properties and the IB, except for the TS. The OSB panels made from aspen obtained better bending properties, while the IB and TS properties were lower than those of the OSB black spruce panels. The results indicate that black spruce strands obtained from the Eastern Canadian softwood lumber industry are suitable for OSB production, but more work is required to reduce the TS.

This research examined the influence of the compositions between coconut fiber (Cocos nucifera) and wood particles (Pinus taeda L. and Eucalyptus saligna) on physico-mechanical properties of homogeneous particleboards. The exploratory study was carried out under Tukey’s contrast test of means, at 5% significance level, with the following compositions: 100% coconut fiber (F100 P0 E0); 50% coconut fiber, 25% pine particles, and 25% eucalyptus particles (F50 P25 E25); and 50% of pine particles and 50% of eucalyptus particles (F0 P50 E50), with particle moisture content between 0% to 2% and 10%, in mass, of polyurethane-castor oil (PU-Castor) resin. Three panels were produced for each composition. The physico-mechanical properties such as density, moisture content, swelling in thickness after 24 h of immersion in water, perpendicular tensile strength, static bending strength, and modulus of elasticity were evaluated using standard methods. The results obtained indicated the potential for using coconut fiber for the production of homogeneous particleboards in view of the minimum criteria required by the normative documents, with emphasis on the physical property of swelling after 24 hours, which obtained a statistically equivalent average relative to the treatment that contained only wood particles.

The cantilevered leg joint commonly used in modern wood furniture was studied by numerical and experimental methods. A novel joint was proposed and compared with the typical joint commonly used in the cantilevered leg. Both of them were made of beech wood (Fagus orientalis Lipsky). The experimental results showed that the bending moment capacity of the novel joint was remarkably higher than the typical joints, which confirmed that the novel structure had a better mechanical performance. The numerical analysis was conducted according to GB/T 10357.3 standard, the results showed that the stresses of the typical joint were mainly concentrated on the wooden components, while the stresses of the novel joint were concentrated on the metal connectors. The stress concentration obtained by the finite element method (FEM) was consistent with the failure modes of the experimental tests, which provides a reliable method for evaluating and optimizing the novel furniture structure.