University of Oulu

ACS Sustainable Chem. Eng. 2021, 9, 2, 883–893,

One-step twin-screw extrusion process to fibrillate deep eutectic solvent-treated wood to be used in wood fiber-polypropylene composites

Saved in:
Author: Taheri, Hesam1; Hietala, Maiju1; Suopajärvi, Terhi1;
Organizations: 1Fiber and Particle Engineering Research Unit, Faculty of Technology, University of Oulu, P.O. Box 4300, FIN-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 11.8 MB)
Persistent link:
Language: English
Published: American Chemical Society, 2021
Publish Date: 2021-05-12


Bio-based wood materials are preferable for composites because of their sustainability, but adequately dispersing wood fibers in polymers can be difficult and costly. Our approach was to pretreat the wood with a green solvent system, allowing the composite to be extruded in a single step, simplifying the process, and reducing the overall cost. This study investigates the fibrillation of untreated wood sawdust (W) and deep eutectic solvent-treated wood sawdust (DESW) using a one-step twin-screw extrusion (TSE) process. The results of the analysis of wood fractions and optical microscopy confirmed that the one-step extrusion process resulted in fibrillation of both treated and untreated wood material. The width of the original wood particles was reduced by more than 99% after a one-step TSE for both untreated and DES-treated wood. The size reduction of the DESW was slightly greater than that of the untreated wood, and fibrillation was further confirmed by rheological analysis. The fibrillated wood was then compounded with polypropylene (PP) to produce a wood fiber-polypropylene composite with 50 wt % wood content. The elastic modulus of both untreated and treated extruded composites was higher than that of neat PP. The tensile strength and strain at break for the DESW-PP composite slightly increased in comparison to the untreated W-PP composite. Furthermore, DES treatment of wood resulted in a darker color and increased hydrophobicity of the material.

see all

Series: ACS sustainable chemistry & engineering
ISSN: 2168-0485
ISSN-E: 2168-0485
ISSN-L: 2168-0485
Volume: 9
Issue: 2
Pages: 883 - 893
DOI: 10.1021/acssuschemeng.0c07750
Type of Publication: A1 Journal article – refereed
Field of Science: 215 Chemical engineering
216 Materials engineering
Funding: We thank Business Finland (formerly The Finnish Funding Agency for Technology and Innovation, TEKES) for its financial support (grant no. 1841/31/2014) and Bio4Energy Swedish Strategic Research Program for financial support.
Copyright information: © 2021 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium,provided the author and source are cite