Cell Wall Bulking by Maleic Anhydride for Wood Durability Improvement

Exploration of Optimal Reaction Conditions for Constructing Hydrophobic Polymers with Low Deformation to Facilitate the Dimensional Stability of Laminated Bamboo Lumber

The environmental moisture changes would result in the deformation and cracking of laminated bamboo lumber (LBL) easily due to the unreleased internal stress, leading to poor durability. In this study, a hydrophobic cross-linking polymer with low deformation was successfully fabricated and introduced in the LBL by polymerization and esterification to improve its dimensional stability. In an aqueous solution, the 2-hydroxyethyl methacrylate (HEMA) and Maleic anhydride (MAh) were employed as the base compounds for synthesizing the copolymer of 2-hydroxyethyl methacrylate and maleic acid (PHM). The hydrophobicity and swelling performance of the PHM was adjusted by controlling the reaction temperatures. PHM-modified LBL's hydrophobicity as indicated by the contact angle, increased from 58.5° to 115.2°. The anti-swelling efficiency was also improved. Moreover, multiple characterizations were applied to clarify the structure of PHM and its bonding linkages in LBL. This study demonstrates an efficient avenue to facilitate the dimensional stability of LBL by PHM modification and sheds new light on the efficient utilization of LBL using a hydrophobic polymer with low deformation.

Wood in office spaces: The impact of different wooden furniture on aesthetic evaluation

In modern urban life, individuals are spending an increasing amount of time in the office. However, working in an uncomfortable office space for extended periods can affect the physical and mental health of employees. On this basis, it is particularly important for employees to build a comfortable and healthy office environment that is conducive to their work. The present study aimed to explore the use of wood in office furniture to build a comfortable and healthy work environment. The use of wood in office spaces can effectively relieve the mental fatigue of employees. Focusing on wooden office furniture, this study explores its influence on the aesthetic evaluation of wooden office spaces by manipulating the wood color and coverage of the wooden furniture placed in office spaces. Experimenting with these changes will optimize the application of wood in office spaces, improve employees' mental health. The results show that wood color and coverage significantly impact the aesthetic evaluation of wooden office spaces. People exhibit higher aesthetic evaluations of light and medium wood-colored office spaces and prefer spaces with low wood coverage. The findings of this study provide a reference for the use of wooden furniture to optimize workplaces.

Research Progress of Wood Cell Wall Modification and Functional Improvement: A Review

The modification of wood cell walls is based on the characteristics of the chemical composition and structure of the cell wall. Various physical and chemical modifications to these characteristics enhance the original properties of the cell wall and give additional functionality. Through complex modification, wood has also obtained the opportunity to become a multifunctional material. Scholars have paid more attention to the microscopic properties of the cell wall with continuous enrichment of modification methods and improvement of modification mechanisms. This article summarizes the methods of cell wall modification in recent years and proposes prospects for future development: (1) innovation of modifiers and combination with modification mechanism, as well as improvement of cell wall permeability; (2) the application directions of cell wall structures; and (3) the application of nano-technologies in cell wall modification. This review provides further ideas and technologies for wood modifications.

Effect of Glue Spreads on the Structural Properties of Laminated Veneer Lumber from Spindleless Rotary Veneers Recovered from Short Rotation Hevea Plantation Logs

Unproductive young rubber trees (15 years old) with smaller diameters (15 to 18 cm) compared to conventional rubber logs, harvested at the age of 25 years old, were selected for the production of laminated panels. Spindleless rotary veneer peeling was applied to logs from short-rotation rubber forest plantations to produce veneers for structural purposes. This raises questions about the utilization of these small-diameter logs with respect to its effect on the quality of veneer and laminated panels produced. This study examines the effect of the glue spread rates on the physical and mechanical properties of rubberwood laminated veneer lumber (LVL). Analysis of variance shows that the application of a 280 g/m² glue spread rate significantly improved the density, water absorption and dimensional stability of rubberwood LVL. The mechanical properties of rubberwood LVL produced with a 200 g/m² glue spread rate met the minimum requirement for the 2.1E-3100F stress class; 91.05 MPa for the modulus of rupture in the flatwise direction and 50.23 MPa for compressive strength parallel to the longitudinal axis. The modulus of elasticity in the flatwise direction of 11,189.55 MPa reached the minimum requirement for the 1.5E-2250F stress class.

Hydrophobization and Photo-Stabilization of Radiata Pinewood: The Effect of the Esterification on Thermal and Mechanical Properties

Wood protection through chemical modification has received increasing interest over the last decades due to the environmental issues related to conventional biocides or protecting products. Consequently, a wide range of new treatments are developed in laboratories, which are later scaled up in the industrial environment. The main goal of modifying wood for indoor–outdoor application is to change its hydrophilic character, which in turn improves the intrinsic properties of the material and its durability against external factors. Wood can be esterified through its hydroxyl groups to obtain a hydrophobic and photo-stable material. Chemical modifications of Pinus radiata D. Don wood using hexanoyl chloride (P6), dodecanoyl chloride (P12), and stearoyl chloride (P18) were carried out at different concentrations. Esterification was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) technique combined with a discriminatory analysis. Weight percent gain was associated with the number of carbons of the aliphatic chain of the fatty acid (P6 > P12 > P18). Moreover, an increase of wood density as a consequence of modification treatments was observed. A substantial improvement of the hydrophobicity of wood was observed by dynamic contact angle measurements. In addition, the effect of ultraviolet (UV) radiation on color changes was reduced with the treatments. Furthermore, the P6 treatment presented acceptable values of modulus of elasticity (MOE) and modulus of rupture (MOR), being suitable for similar mechanical uses as non-treated pinewood. However, only treatments P12 and P18 enhanced thermal resistance of the pinewood in an oxidative atmosphere.

Preparation of Wood-Based Panel Composites with Poplar Veneer as the Surface Layer Modified by In-Situ Polymerization of Active Monomers

Wood-based panels covered by melamine-impregnated paper are widely used in floors and furniture, due to its good surface texture, hardness, wear resistance, and waterproof function. However, there are still some problems, such as formaldehyde release from the impregnated resin, non-wood touch, and complex preparation processes. Therefore, this study designed glycidyl methacrylate (GMA) and ethyleneglycol dimethacrylate (EGDMA), combined with maleic anhydride (MAN) as a reactive catalyst, to build an active monomers system. It was first impregnated into poplar veneers, and then in-situ polymerized within the veneer using a hot pressing process, which realized the gluing of the veneer onto the wood-based panel substrate, synchronously. Such treatment aims to obtain wood-based panel composites decorated by the modified veneer, with real solid wood touch feeling, satisfied surface properties, and environment friendly glue bonding. The results indicated that the optimized reaction ratio of the active monomers (GMA:EGDMA) was 2:1 (molar ratio), and the maleic anhydride addition accounted for 6 wt.% of the total monomers. Under the optimized hot pressing condition, the modified veneer closely bonded to the wood-based panel substrate without obvious interfacial gaps. The hardness, abrasion resistance, modulus of rupture, and water resistance of the composites were significantly improved. Such results indicate that the treatment realized the perfect merging of solid wood touch feeling, environment friendly feature, and excellent properties of the composite. It was highly expected to replace the traditional melamine-impregnated paper to decorate wood-based panels, and could be potentially applied as surface decorating materials in wide areas of desktop, floor, cupboard, wardrobe, and so on.