Production of nanocellulose gels and films from invasive tree species

• Autor(a) principal: Almeida, R. O.
• Data de Publicação: 2021
• Outros Autores: Ramos, A., Alves, L., Potsi, E., Ferreira, P. J. T., Carvalho, M. G. V. S., Rasteiro, M. G., Gamelas, J. A. F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/95604; https://doi.org/10.1016/j.ijbiomac.2021.08.015
• topic: Cellulose nanofibrils; Circular economy; Films; Invasive species; Inverse gas chromatography; Waste valorisation

Wood/wastes from invasive tree species Acacia dealbata and Ailanthus altissima were used to produce high-value added nanocellulose. Firstly, bleached pulps were produced from the wood of these tree species after kraft cooking. Afterwards, the resultant pulps were pre-treated by TEMPO-mediated oxidation (Acacia dealbata) or enzymatic hydrolysis (Ailanthus altissima) followed by high-pressure homogenization. Hydrogels were obtained and characterized for their main physical and chemical properties, including rheology and evaluation of the surface properties of the freeze-dried materials by inverse gas chromatography. Results showed that micro/nanofibrils could be obtained from the wood of these invasive species. Rheometry studies showed that Acacia-TEMPO cellulose nanofibrils form strong gels with high yield stress point and viscosities (reaching ca. 100,000 Pa·s). Additionally, the surfaces of the obtained nanocelluloses showed a dispersive component of the surface energy near 40 mJ/m2 and a prevalence of the Lewis acidic character over the basic one, as typical for cellulose-based materials. Finally, films with good mechanical and optical properties could be obtained from the cellulose hydrogels. Acacia-TEMPO film (produced by filtration/hot pressing) showed a tensile strength of 79 MPa, Young's modulus of 7.9 GPa, and a transparency of 88%. The water vapor barrier, however, was modest (permeability of 4.9 × 10-6 g/(Pa·day·m)).