Water-assisted extrusion and injection moulding of composites with surface-grafted cellulose nanocrystals – An upscaling study
Journal article, 2021

The large-scale surface modification of cellulose nanocrystals (CNC) was carried out to produce CNC-containing composites, in a scale of 3 kg, using industrial-scale melt processing techniques such as twin-screw extrusion and injection moulding. Two different polymer matrices, ethylene-acrylic acid copolymer (EAA) and low-density polyethylene (LDPE), were reinforced with 10 wt% unmodified cellulose nanocrystals (CNC) or surface-treated CNC, where a 2-hydroxyproyl-N-diallyl group had been grafted onto the sulphate half-ester groups on the CNC surfaces. This was achieved by mixing an aqueous CNC dispersion and the polymer pellets directly in the twin-screw extruder followed by a second dry compounding step prior to shaping by injection moulding. The injection-moulded materials were characterized with respect to their mechanical properties and thermal stability. The addition of 10 wt % CNC resulted in all cases in an increase in the yield strength and stiffness by 50–100%, most significantly for the EAA based composites. There were indications of the presence of a stable interphase and a percolating network in the EAA-based materials, according to dynamic-mechanical measurements. A reduction in thermal stability was observed for the melt-processed samples containing diallyl-modified CNC and discoloration in the EAA based samples.

Extrusion

Injection moulding

Cellulose nanocrystals

Mechanical properties

Author

Lilian Forsgren

Chalmers, Industrial and Materials Science, Engineering Materials

Abhijit Venkatesh

Chalmers, Industrial and Materials Science, Engineering Materials

Florian Rigoulet

Chalmers, Chemistry and Chemical Engineering

Karin Sjövold

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry, Physical Chemistry

Wallenberg Wood Science Center (WWSC)

Gunnar Westman

Wallenberg Wood Science Center (WWSC)

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Mikael Rigdahl

Chalmers, Industrial and Materials Science, Engineering Materials

Antal Boldizar

Chalmers, Industrial and Materials Science, Engineering Materials

Composites Part B: Engineering

1359-8368 (ISSN)

Vol. 208 108590

Driving Forces

Sustainable development

Subject Categories

Materials Chemistry

Composite Science and Engineering

Areas of Advance

Materials Science

DOI

10.1016/j.compositesb.2020.108590

More information

Latest update

1/21/2021