Abstract
Wood surface modification is a comprehensive concept which, in time, turned out to be as successful as challenging when it comes to improve the resistance of wood during its life cycle in both indoor and outdoor applications. The initial approaches have aimed at simple methods with immediate results. Nowadays, the paradigm has slightly changed due to the scientific and technical advances, and some methods has become intermediate stages in more complex processes, after being used, for long time, as stand-alone procedures. The esterification was employed as a convenient method for wood surface modification due to the high amount of free hydroxyl groups available at the surface of wood and other lignocellulosic materials. Therefore, different esterification approaches were tested: activated condensation with carboxylic acids (monocarboxylic, as well as dicarboxylic acids, fatty acids, etc.) in the presence of condensation activating agents (such as trifluoroacetic anhydride); reaction with β-halogen-substituted carboxylic acids; esterification using carboxylic acids derivatives (acyl chlorides, anhydrides) or even multifunctional carboxylic acids (i.e., tricine). Thus, wood with improved dimensional stability and weathering resilience, higher fire resistance, enhanced hydrophobic character, and mechanical durability was obtained. This paper offers an overview of some of the most recent advances reported in the field, presented in a systematic manner, using the type of reaction as classification criterion. The main improvements will be outlined in a critical assessment in order to provide an useful tool for a wise choice in future applications.
Highlights
2, where one can observe the structural units water present in the wood substrates is essential, because a moisture level of around appears that undergo various changes. These are functional groups located on the glucose monomer in to be necessary an esterification reaction in the optimal conditions, while above this value the present cellulose chainsfor from wood structure, when carbon atoms occupying various positions in the water hydrolyses the anhydrides with formation of the corresponding carboxylic acid
Composites where citricacid acid (CA) was bond to either wood or magnetite particles were prepared and their study indicated that the CA-coated magnetite/wood was the material with a remarkable ability to retain metal ions (Cu2+, Co2+ and Zn2+ ) [176], as the process was fast and spontaneous, endothermic, and selective so far it could be used for analytic purposes
The modified wood showed significantly improved mechanical properties, resistance toward water and dimensional stability: water repellence and dimensional stability increased by 50% and 45% respectively, when spruce, pine or poplar and other wood species were submitted to this particular esterification [208,210]
Summary
Wood surface modification is a comprehensive concept which, in time, turned out to be as increasingly successful as challenging when it comes to turn wood species into high-value products. Many approaches envisaging wood modification [1,2,3,4,5,6,7,8] include treatment processes, defined as chemical, biological (e.g., enzymatic modification for hydrophobicity), mechanical or physical methods All these methods are applied to modify wood with the scope to acquire enhanced properties for the sustainable service life of the resulted material which should not pose any environmental hazards related to its toxicity during all life cycle period (referring to use, recycling or disposal issues). It is moisture-, bio-, fire- or UV-resistant agents on the wood surfaces, as the final stage of wood effective for an improved wood protection against weathering processes under environmental exposure processing It is effective for an improved wood protection against weathering processes under conditions in exterior uses.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
