Rheological and mechanical properties of dispersed cellulose nanofiber/polylactic acid composites produced by a liquid-supercritical CO2 water removal process

Published: 2025

Author(s):

Manley, Alyson
Es-haghi, Shams
Tripp, Carl

Publication Name: Cellulose

Publication URL: https://doi.org/10.1007/s10570-025-06850-y

Research Area:

Nanocellulose

Keywords:

Cellulose nanofibers (CNFs), poly(lactic acid) PLA, Scale up, Supercritical CO2 (SC-CO2), Tensile strength

Abstract:

We report on the rheological and mechanical properties of bio-sourced composites composed of dispersed cellulose nanofibers (CNFs) in polylactic acid (PLA). The composites were generated using a liquid CO2 (L-CO2) solvent exchange/supercritical CO2 (SC-CO2) venting procedure. This SC-CO2 dewatering process maintained the nano-dimensional architecture of the CNFs and led to a homogeneous distribution of CNFs within the PLA matrix. Rheological data obtained for the SC-CO2 dewatered composite at 2, 5, 10, and 20 wt% CNFs showed network formation of the CNF within the PLA matrix. At 10 wt% SC-CO2 CNF concentration, we obtained a 23% increase in tensile modulus and a 6% increase in tensile strength relative to neat PLA. These results are comparable to the literature values of 30% and 9% increases in tensile modulus and strength obtained using the solvent casting method with chloroform. In contrast, PLA composites containing spray dried CNFs (SDCNFs) showed no difference in tensile modulus or strength compared to neat PLA.