Nanocelluloses produced from wood pulp are widely studied for various economic applications. Most studies of cellulose nanofibrils (CNF) use lignin-free fibres obtained from bleached pulps; however, unbleached fibres with residual lignin may also be used to obtain lignocelluloses nanofibrils (LCNF). Research on lignocellulose nanofibrils is a recent subject in the field; thus, the aim of the present study was to determine the ultrastructure of lignocellulose nanofibrils compared to cellulose nanofibrils produced from the same raw material. Understanding of nanoparticle properties is of great relevance for their various applications; therefore, complete characterisation of the chemical, physical, and morphological structures of LCNF and CNF produced from pine and eucalyptus woods was performed. Unbleached cellulosic fibres are a viable alternative for LCNF production, which has properties comparable to that of traditional CNF production that uses lignin-free fibres. LCNF from pine and eucalyptus were obtained with 4.0 % and 1.8 % residual lignin, respectively. The nanofibrils had high thermal stability because LCNF had a higher maximum degradation temperature. Due to the low interaction of lignin with water, LCNF had a lower water retention value than CNF.

Wood from planted forests is the main input in the charcoal production chain. However, the heterogeneity of charcoal, in terms of its physical, chemical and mechanical properties, and the low yield in production processes is among the main problems faced by industries. To select the best clones for the production of charcoal for steelmaking, the objective of this work was to evaluate the properties of wood, in addition to the yield and quality of charcoal from different genotypes of Eucalyptus and Corymbia. Five clones of Eucalyptus spp., 8 years old and one of Corymbia torelliana x Corymbia citriodora, 4 years old were studied. In the wood were determined the basic density, structural chemical composition, thermogravimetric analysis (TG/DTG), crystallinity index and higher heating value. Carbonizations were carried out in a muffle oven, with a total time of 270 minutes, starting at 150°C and ending at 450°C. The gravimetric yield, apparent density, higher heating value and proximate analysis of charcoal were determined. The wood basic density varied between 477 and 652 kg/m³, with the highest value observed for the Eucalyptus cloeziana clone. This clone also had the highest total lignin content (32.6%), the highest charcoal yield (36.3%) and charcoal with the highest apparent density (466 kg/m³). The two clones of Eucalyptus urophylla had the highest heating value for charcoal, whose mean was 7545 kcal/kg. The clone of Corymbia torelliana x Corymbia citriodora, having an apparent density greater than 500 kg/m³ at 4 years of age, stood out in terms of productivity. All evaluated clones have potential for charcoal production, however, the Eucalyptus cloeziana clone stood out positively, being the most suitable for charcoal production.

The wood heat treatment results in the partial degradation of its chemical constituents, mainly cellulose and hemicellulose, reducing the hygroscopicity of the material. This process improves the dimensional stability and resistance to biodeterioration and worsens the mechanical resistance. This work aimed to evaluate the effect of heat treatment on the physical, anatomical, chemical, and mechanical properties of Fraxinus excelsior wood. In untreated and heat-treated wood, the pH, buffering capacity, basic density, equilibrium moisture content, shrinkage, wood anatomy, thermogravimetric behavior, and chemistry by conventional and FTIR methods were determined.