Thermal stability increase in metallic nanoparticles-loaded cellulose nanocrystal nanocomposites

• Published in: Carbohydrate polymers 2017-09, Vol.171, p.193-201
• Main Authors: Goikuria, U., Larrañaga, A., Vilas, J.L., Lizundia, E.
• Format: Article
• Language: English
• Subjects: Activation energy; Biopolymers; Cellulose nanocrystals; Metallic nanoparticles; Nanocomposites; Thermal stability
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2017.05.024

In this work we explore nanocomposite approach as an alternative method to increase the intrinsic poor thermal stability of CNCs obtained after sulphuric acid-assisted hydrolysis of cellulose. [Display omitted] •CNC-based free-standing nanocomposite films have been fabricated by EISA.•The effect of ZnO, SiO2, TiO2, Al2O3 and Fe2O3 on the thermodegradation is studied.•Kissinger and Ozawa-Flynn-Wall thermodegradation activation energies were determined.•Thermal stability is increased up to 75°C after 10wt% Fe2O3 and ZnO addition.•We show a low-cost and green strategy to overcome the poor thermal stability of CNCs. Due to the potential of CNC-based flexible materials for novel industrial applications, the aim of this work is to improve the thermal stability of cellulose nanocrystals (CNC) films through a straightforward and scalable method. Based of nanocomposite approach, five different metallic nanoparticles (ZnO, SiO2, TiO2, Al2O3 and Fe2O3) have been co-assembled in water with CNCs to obtain free-standing nanocomposite films. Thermogravimetric analysis (TGA) reveals an increased thermal stability upon nanoparticle. This increase in the thermal stability reaches a maximum of 75°C for the nanocomposites having 10wt% of Fe2O3 and ZnO. The activation energies of thermodegradation process (Ea) determined according to Kissinger and Ozawa-Flynn-Wall methods further confirm the delayed degradation of CNC nanocomposites upon heating. Finally, the changes induced in the crystalline structure during thermodegradation were followed by wide angle X-ray diffraction (WAXD). It is also observed that thermal degradation proceeds at higher temperatures for nanocomposites having metallic nanoparticles. Overall, experimental findings here showed make nanocomposite approach a simple low-cost environmentally-friendly strategy to overcome the relatively poor thermal stability of CNCs when extracted via sulfuric acid assisted hydrolysis of cellulose.