Photodegradation of different nanocellulose substrates

Abstract

Abstract The increased interest in the development of sustainable materials for printed electronics necessitates durability studies in their operating environments. Hence, in this paper, the effects of photodegradation on five different nanocellulose and four reference substrates were examined. Changes in optical, surface, and mechanical properties were analyzed in detail by studying the color intensity, total color difference, contact angle, surface energy, Fourier transform infrared spectroscopy, and bending resistance of the substrates before and after photodegradation treatment. The nanocellulose substrates analyzed in this study were cellulose nanofibers (made using sodium washing, supermasscolloider, three passes in microfluidizer and cast drying) (CNF3Cs), acetylated cellulose nanofibers (ACNFs), cellulose nanofibers (made using six passes in microfluidizer, air pressure filtration, and hot pressing) (CNF6Hs), cellulose nanofibers produced using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidization (TCNFs), and cellulose nanofibers containing lignin residuals made using TEMPO-mediated oxidation (LTCNFs). All examined properties changed significantly for CNF3C, LTCNF, and opaque poly(ethylene terephthalate) (oPET) substrates. The newspaper (NP) displayed the largest changes in all properties except for the bending resistance. CNF6H, TCNF, polyimide (PI), and transparent poly(ethylene terephthalate) (tPET) substrates demonstrated less degradation compared to the substrates mentioned above. The ACNF substrate did not show any notable changes during the photodegradation treatment. Thus, this study demonstrates that especially ACNF films could be suitable and durable alternatives to conventional plastic substrates, such as PET or PI, used in printed electronics.