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New processing methods for cellulose nanocomposites

 

Polymer composites based on cellulose nanocrystals (CNCs) have attractive properties that make them interesting materials to work with. So far, however, industrially useful production processes for these materials have been lacking. The research project developed principles for easy fabrication of CNC-based nanocomposites.

Project description (completed research project)

The research project provided the scientific basis for developing easily scalable processes for fabricating nanocomposites comprised of CNCs and technologically relevant plastics. In a first step, the researchers developed processes for fabricating homogeneous blends of both components with the best possible mechanical properties. In a second step, the scientists investigated nanocellulose can be protected from the damage it typically sustains upon exposure to high temperature and shear in conventional melt processing. In a third step, the nanocellulose was equipped with a universal compatibiliser that facilitates blending with different types of plastics.

Background

A wide range of nanocomposites made from different plastics and CNCs have been fabricated in the past. However, up to now it has not been possible scale up their preparation from the laboratory to commercial production scale. As a result, the materials are still technologically of little use and have not yet led to any major industrial applications.

Aim

The research project aimed to develop new, scalable and robust methods for producing nanocomposites using technologically relevant plastics and CNCs from wood. This should pave the way to industrial production of CNC materials for the Swiss timber industry.

Relevance

The insights gained from the project have led to better understanding of the relationship between the processing, structure and properties of CNC/polymer nanocomposites. This should help in developing new fabrication methods and material concepts. Significant progress has been made in all the process steps, which brings industrial production of nanocomposites containing CNCs (e.g. from wood) much closer and paves the way to the industrial production of CNC composites.

Results

The results reveal a relationship between shear forces, CNC degradation and the mechanical properties of the materials. Blending at low shear produced materials which showed optimal mechanical properties, did not degrade well-dispersed CNCs and the composites retained their original morphology. The results of this study were successfully applied in manufacturing nanocomposites based on CNCs and low-density polyethylene (LDPE), polyamide and various polyurethanes. The data show that it is possible to achieve significant mechanical improvement through the use of highly scalable blending processes under low shear.

Original title

Processing of polymer/cellulose nanofiber composites

Project leader

  • Prof. Christoph Weder, Adolphe Merkle Institut, Universität Freiburg Schweiz

 

 

Further information on this content

 Contact

Prof. Christoph Weder Adolphe Merkle Institute
University of Fribourg
Rue de l'Ancienne Papeterie 1723 Marly +41 26 300 94 65 christoph.weder@unifr.ch