Funcionalização da madeira de eucalipto

Abstract

In recent years, under a scenario characterized by environmental concern and a desire for sustainability, wood has been highlighted as an environmentally friendly material of high quality. This is because wood is renewable, non-toxic, biodegradable, and has an organized polymeric structure. In light of this, researchers have demonstrated the possibility of adding functionality to wood through physical-chemical modifications, however such processes are expensive, use toxic reagents, and waste liquids. Usually, wood functionalization studies are conducted with balsa wood, due to its anatomical structure that facilitates cell wall modifications and reagent impregnation. However, the functionalization of wood species with medium density wood, such as those of the Eucalyptus genus, is still a challenge. Therefore, the aim of this study is to functionalize eucalyptus wood through environmentally friendly processes, with low energy consumption and no waste generation. To this purpose, a lignin modification technique was applied by photocatalytic oxidation assisted by ultraviolet radiation and chemical vapor deposition of methyltrimethoxysilane (silanization with MTMS), which resulted in two distinct products without waste production, quickly and at low cost. The first product obtained was whitish colored photonic wood with lignin retention higher than 70% and high luminosity values (L > 93), suitable for applications in materials and devices aimed at managing optical properties. The second product is a wood-based material that combines hydrophobicity with high reflectance in the visible range. Its ability to absorb radiated energy in the 300 to 700 nanometer range was reduced by up to 70% and the contact angle was greater than 110°, so it can be applied for radiative cooling and increasing the energy efficiency of buildings. The research developed in this thesis is highlighted by the use and improvement of the lignin modification technique and degradation of its chromophoric groups, as well as, by developing a new product that combines two new functionalities to wood in a waste free way and without using toxic chemicals. Therefore, it is aligned with the knowledge frontier around wood functionalization with the aim of developing new environmentally sustainable products.