Spray deposited cellulose nanofibril films: a recyclability study

Synthetic packaging has excellent performance, but most of them becomes a waste after their use and thus, poses serious concerns to the environment and consumer health. Considering current circumstances, the demand for sustainable packaging that is either recyclable or biodegradable if discarded has increased tremendously in last few years. Cellulose nanofibril (CNF) films are emerging as a sustainable packaging; however, their high energy consumption associated with the production of fibres and reduced properties on recycling are serious concerns. The aim of this study is to assess the recycling characteristics of spray deposited CNF films. For this purpose, the CNFs were recycled at different revolutions (75 × 10³ to 999 × 10³) in a laboratory disintegrator, followed by screening and their physical, barrier and environmental characteristics were evaluated. Results showed that recycled CNF films at 300 × 10³ revolutions had identical barrier performance as compared with the non-recycled films. Additionally, the films after first recycling have maintained their mechanical properties without compromising their dimensional stability. However, the mechanical performance and transmittance of these films after the 2nd recycling have slightly reduced due to the agglomeration of the fibres as affirmed by the SEM images. The CNF films showed slightly higher environmental impact in terms of their embodied energies than conventional packaging; however, these impacts are expected to be lower on possibly further recycling of these films. The ease of recycling of these films without compromising the dimensional stability is an excellent route to contribute towards global sustainability. Graphical Abstract: [Figure not available: see fulltext.]