Hybrid films of cellulose nanofibrils, chitosan and nanosilica-Structural, thermal, optical, and mechanical properties

Mostafa Y Ismail; Minna Patanen; Juho Antti Sirviö; Miikka Visanko; Takuji Ohigashi; Nobuhiro Kosugi; Marko Huttula; Henrikki Liimatainen

doi:10.1016/j.carbpol.2019.04.065

Hybrid films of cellulose nanofibrils, chitosan and nanosilica-Structural, thermal, optical, and mechanical properties

Carbohydr Polym. 2019 Aug 15:218:87-94. doi: 10.1016/j.carbpol.2019.04.065. Epub 2019 Apr 27.

Authors

Mostafa Y Ismail¹, Minna Patanen², Juho Antti Sirviö¹, Miikka Visanko¹, Takuji Ohigashi³, Nobuhiro Kosugi³, Marko Huttula², Henrikki Liimatainen⁴

Affiliations

¹ Fibre and Particle Engineering, University of Oulu, P.O. Box 4300, FI-90014, Finland.
² Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014, Finland.
³ UVSOR Synchrotron Facility, Institute for Molecular Science, Myodaiji, Okazaki, 444-8585, Japan.
⁴ Fibre and Particle Engineering, University of Oulu, P.O. Box 4300, FI-90014, Finland. Electronic address: Henrikki.Liimatainen@oulu.fi.

PMID: 31221348
DOI: 10.1016/j.carbpol.2019.04.065

Abstract

Organic-inorganic hybrid films were fabricated from cellulose nanofibrils (CNF) and nanosilica (5-30% wt) embedded in a chitosan (Chi) biopolymer matrix using a slow evaporation method. The self-standing films exhibited high strength and modulus up to 120 ± 5 MPa and 7.5 ± 0.4 GPa, respectively, which are remarkably high values for biopolymer/chitosan hybrids. Scanning electron microscopy showed that the nanosilica is formed of larger aggregates within the lamellar CNF network structure. This observation was further confirmed using synchrotron-based scanning transmission x-ray microscopy (STXM) with the capability to determine the spatial and chemical distribution analysis of the constituents of films. It is interesting that the thermal stability of the hybrid films improved as the nanosilica content increased. Furthermore, the nanosilica effectively filled the pores in the CNF network, thus decreasing the UV transmission and the visible light transmittance of the films.

Keywords: Chitosan; Nanocomposites; Nanopaper; STXM; Spectroscopy; XPS.