Surface Activation of Polylactic Acid-Based Wood-Plastic Composite by Atmospheric Pressure Plasma Treatment.

Philipp Sauerbier,Gerrit Renner,Robert Köhler,Holger Militz

doi:10.3390/ma13204673

Abstract

Wood-plastic composite (WPC) based on a polylactic acid (PLA) matrix is a promising material since it is biobased, degradable, sustainable, and 3D printable. However, due to its coloring, visible layers after 3D-printing, and small build volumes of these printers, a coating or gluing of parts might be required. This study investigates the influence of a dielectric barrier discharge (DBD) plasma treatment of PLA-based WPC to activate the surface and improve, e.g., coating capabilities. X-ray photoelectron spectroscopy (XPS) measurements showed the oxidation of the surface due to the formation of carbonyl and carboxyl groups. Laser scanning microscopy revealed a surface roughening after the treatment. Contact angles of water and diiodomethane decreased significantly after the plasma treatment and the consecutively calculated surface free energy increased. Finally, two practical adhesion tests revealed an improvement of the applied acrylic dispersion coating’s adhesion to the WPC surface: The assigned cross-cut class improved, and the pull-off strength increased from 1.4 to 2.3 N/mm2.

Highlights

Wood-plastic composites (WPCs) are a promising material with a growing market that is expected to expand further, driven by increasing attention and demand for environmentally friendly and sustainable products [1]
Life cycle assessment (LCA) revealed the ecological superiority of natural fibers compared to glass fibers [2], while Feifel et al showed with an LCA that WPC flooring is a tenable ecological alternative to tropical wood even at the first use
Studies by Bütün et al and Krause et al showed that recovered fibers from fiberboards are a suitable material source for the WPC production

Summary

Introduction

Wood-plastic composites (WPCs) are a promising material with a growing market that is expected to expand further, driven by increasing attention and demand for environmentally friendly and sustainable products [1]. Life cycle assessment (LCA) revealed the ecological superiority of natural fibers compared to glass fibers [2], while Feifel et al showed with an LCA that WPC flooring is a tenable ecological alternative to tropical wood even at the first use. The environmental impact can be significantly reduced by material recycling [3]. Studies by Bütün et al and Krause et al showed that recovered fibers from fiberboards are a suitable material source for the WPC production. Utilizing fibers from medium-density fiberboards revealed beneficial effects on the produced WPC’s physicomechanical properties [4,5]

Methods

Discussion

Conclusion