Enhancing the value of lignocellulosic biomasses through the production of bionanocomposites

M. Pastore, J. Pires, L. Gomes, V. G. L. Souza, W. Zegada-Lizarazu, A. Monti, A. L. Fernando

Research output: Contribution to journalConference articlepeer-review


Cellulose can be isolated from the lignocellulosic fibers and then depolymerized to give rise to nanocrystalline cellulose (CNC), an extraordinary nanometer-scale bio-based material with applicability in diverse technological areas. However, not all cellulose hydrolyze to the point of being converted to nanometric size after the reaction is finished. Therefore, the aim of the work was to optimize the extraction of NC from different lignocellulosic biomasses (sorghum, Sorghum bicolor (L.) Moench and sunn hemp, Crotalaria juncea L.) and to evaluate its application as a reinforcing agent in chitosan biofilms. The nanocellulose was obtained via alkaline pretreatments with NaOH, followed by a bleaching and acid hydrolysis. In the alkali pre-treatment process optimization, some parameters were tested, namely time of reaction and temperature, and taking into consideration a scale up of the process, the time of 2 h 30 min and temperature of 60ºC were chosen as optimum. Comparing the two biomasses, nanocellulose extracted from sunn hemp was easier to process mechanically and also presented a better nanocellulose yield. From sorghum, two different NC were prepared, from inner and outer layer, as the original stems were divided in these two parts which have been processed separately after chopping and grinding. These NC were incorporated in chitosan at 2.5% w/w over the mass of chitosan and the bionanocomposites were characterized: FTIR, mechanical properties, thickness, optical properties, surface color, permeability, solubility, swelling degree, and contact angle. A biofilm made with pristine chitosan was used as the control. The results confirmed that the nanoparticles improved the mechanical properties of the chitosan biopolymer as planned. At the rate of 2.5% NC, it was possible to achieve near 30-40% increment in Tensile Strength (TS), 50-60% in Elastic Modulus (EM) and reduction of Elongation at break (% EAB) by 60-70%, compared with pristine chitosan films. Further, bionanocomposites are slightly more saturated and showed greater ultraviolet light block than the pristine chitosan films, in particular Sunn Hemp NC. Sunn Hemp films also showed a slightly higher thickness than sorghum films and pristine chitosan films. Hence, results indicate that those lignocellulosic crops may afford a source of NC for the production of bionanocomposites.
Original languageEnglish
Pages (from-to)1068-1070
Number of pages3
JournalEuropean Biomass Conference and Exhibition Proceedings
Publication statusPublished - 2023
Event31st European Biomass Conference and Exhibition, EUBCE 2023 - Bologna, Italy
Duration: 5 Jun 20238 Jun 2023


  • biomass valorization
  • lignocellulosic feedstock
  • nanocellulose


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