Naghmeh Nasiri

Title : Transparent high barrier maltitol-cellulose nanocrystal bioplastics for packaging applications

Abstract:

Biobased cellulose nanocrystal (CNC) films can be used in multiple industries as a sustainable replacement for fossil-based plastics. However, their applications are currently restricted by their low barrier properties and brittleness. Tailoring the properties of CNC is critical to sustainably develop their commercial applications. In this study, high-barrier bioplastic films of maltitol, a green polyol plasticizer, and CNCs were prepared using a spray deposition technique. The results showed that the addition of maltitol increased the gas barrier properties, maximum tensile strength, elongation, and translucency of the CNC film. The barrier properties of CNC films plasticized with maltitol were significantly improved over CNC. In particular, films containing 30 wt.% maltitol showed a water vapor permeability of 3.67×10^-12 (g/Pa.s.m) and oxygen permeability of 4.75 (cm³.µm/m².day.Pa) at 50% relative humidity (RH) and 23°C, corresponding to 94% and 78% reductions over CNC films, respectively. The contribution of structural properties and the number of free hydroxyl groups on the barrier properties in the plasticized film was investigated. Both gas porosimetry measurements and cross-sectional SEM microimaging revealed a denser and more aligned layered structure of the film with lower porosity in plasticized samples compared to pristine CNC. The change in the number of free hydroxyl groups and the probability of their interaction with moisture was measured by plotting thermodynamic and kinetics isotherm graphs of the moisture sorption of the films at different RH. The analysis showed at 50% RH plasticized CNC films absorb less moisture over a longer time period, demonstrating that there are less accessible free hydroxyl groups in these films compared to control film, as the hydroxyl groups of the CNCs tend to interact with those of maltitol.

In conclusion, the integration of exceptional transparency, barrier properties, and flexibility in maltitol-plasticized CNC film, utilizing a green and food-safe plasticizer, presents highly promising and sustainable solutions for diverse packaging applications, particularly in food packaging requiring superior barrier performance and flexibility. This new development enables the precise modulation of mechanical, optical, and gas barrier properties in bio-based CNC films, facilitating the engineering of high-performing and environmentally sustainable products.

Audience Take Away

• The research highlights the potential of biobased cellulose nanocrystal (CNC) films as sustainable alternatives to fossil-based plastics across various industries.
• By integrating exceptional transparency, barrier properties, and flexibility in maltitol-plasticized CNC films, the audience will learn about the development of highly promising and sustainable packaging solutions. This innovation offers practical benefits, particularly in food packaging applications requiring superior barrier performance and flexibility, thereby contributing to the reduction of environmental impact and promoting the transition towards a more sustainable future.

Biography:

Naghmeh completed her bachelor’s degree in Polymer Engineering in 2014 at Amirkabir University of Technology (AUT), where she also received a master’s degree in Polymer Engineering in 2016. She worked as a chemical technical consultant and lab analyst prior to commencing her PhD. Currently, she is a PhD candidate under the supervision of Associate Professor Warren Batchelor and Professor Gil Garnier at the Chemical and Biological Engineering Department, Monash University. Her research is focused on Engineering Nano/Micro-Cellulose Fibre Process for Products.