Mechanical, thermal, and water vapor barrier properties of regenerated cellulose/nano-SiO₂ composite films

Abstract: Bionanocomposite films were fabricated by reinforcing regenerated cellulose (RC) with 3-aminopropyl-functionalized silica nanoparticles (nano-SiO₂). The composite films were prepared by dissolving cotton linter RC in a 7% NaOH/12% urea solution followed by the addition of nano-SiO₂ and 5% H₂SO₄ solution. The effects of nano-SiO₂ concentration (1–5 wt% with respect to RC) on the morphology, water vapor permeability (WVP), thermal properties, and mechanical properties of the RC/nano-SiO₂ composite films were evaluated. Morphological studies indicated uniform dispersions of the low-concentration nano-SiO₂ particles in the RC matrix. The tensile strength and modulus were increased by 26% and 15%, respectively, in the presence of 2 wt% of nano-SiO₂ relative to the values of neat RC film. The WVP of the RC/nano-SiO₂ composite films decreased by 22% after reinforcement with 2 wt% nano-SiO₂. The results revealed that there is a potential interaction between RC and nano-SiO₂, resulting in improved thermal and mechanical properties of the RC/nano-SiO₂ composite films compared to those of neat RC film. Graphical abstract: Bionanocomposite films were fabricated by reinforcing regenerated cellulose (RC) with 3-amino propyl functionalized silica nanoparticles (nano-SiO₂). The effects of nano-SiO₂ (1–5 wt% with respect to RC) on the morphology, water vapor permeability (WVP), and thermal and mechanical properties of the RC/nano-SiO₂ composite films were evaluated. This study highlights the potential of organically modified nano-SiO₂ to enhance the properties of RC owing to the ability of nano-SiO₂ to interact with the RC matrix at very low concentrations (2 wt%).[Figure not available: see fulltext.].