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

Abstract

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.

Lignin Nanoparticles with Entrapped Thymus spp. Essential Oils for the Control of Wood-Rot Fungi

“…Innovative methods also comprise the application of nanomaterials, although the possible effects on human and environmental health need to be carefully assessed, as recently reviewed by Papadopoulos and Taghiyari [ 10 ]. In this context, the interest for more environmentally friendly solutions for wood preservation, such as thermal and other modification techniques [ 11 , 12 , 13 , 14 ], as well as impregnation with natural products, has rapidly increased [ 15 , 16 , 17 , 18 ]. Among natural bioactive compounds, essential oils (EOs) have gained considerable interest from researchers regarding their application as biocides [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ].…”

Simultaneous Improvement of Surface Wettability and UV Resistance of Wood with Lignin-Based Treatments

“…To study the changes in the dimensional stability of wood samples at different moisture contents, experimental adsorption and desorption tests were performed and the sorption isotherms and the hysteresis behaviour were analysed. Figure 2 a shows similar isotherms of both untreated and lignin-based treated wood, with a sigmoid shape isotherm (type II), typical adsorption performance of monolayer-multilayer lignocellulosic materials [ 30 , 31 ].…”

Weathering of Wood Modified with Acetic Anhydride—Physical, Chemical, and Aesthetical Evaluation

“…A slightly different behaviour was observed in radiata pine, the only softwood species. The weathering process of unprotected wood enhances we ability due to the degradation of lignin and leaching of the extractives from the surface [41,42].…”