Interface nanocavities in poly (lactic acid) membranes with dispersed
cellulose nanofibrils: Their role in the gas barrier performances
Material and application
Poly lactic acid (PLA) is a biopolymer, obtained from sustainable natural resources and can be produced without fossil oil. It is a 100% biodegradable material and one of the most promising candidates to substitute conventional packing plastics. Cellulose nanofibrils (CNF) can be obtained from cotton and are admixed to PLA in order to improve the gas barrier properties. The final material is supposed to serve as packing material, e.g. in the food industries.
What was the research question to be solved
How does the content of CNF influences the gas barrier properties of PLA? What is the fraction of CNF to obtain the highest gas barrier? How does CNF change the nano structure of PLA?
What results did the PALS method provide
With PALS it was possible to determine the nano pore size of PLA as a function of the CNF content and the temperature. The smallest pore sizes and therefore best gas barrier performances were obtained at a CNF concentration of about 5 %. By increasing the fraction of CNF the intrinsic nano pores start to form larger cavities, which enhances the gas diffusion and decrease the gas barrier properties. The PALS results are in good agreement with gas diffusion measurements, which were done with the same samples.
What was the impact of the achieved result for the user
It could be shown how CNF change the PLA properties on a nano scale. The best mixing ration of CNF in PLA was determined as ~ 5 %. The nanoscopic behavior of the material could be related to macroscopic observations (gas diffusion measurements).
Reference, scientific publication
Interface nanocavities in poly (lactic acid) membranes with dispersed cellulose nanofibrils: Their role in the gas barrier performances
M. Dickmann, S. Tarter, W. Egger, A. Pegoretti, D. Rigotti, R. S. Brusa, R. Checchetto Polymer 202 (2020) 122729