In this paper the effect of an atmospheric-pressure plasma treatment on the surface properties of sugar maple (Acer saccharum March.) and black spruce (Picea mariana (Mill.)) is analyzed by contact angle measurements and water-based coating pull-off tests. The plasma gases used are Ar, N2, CO2, and air. It is found that the wettability with water and the coating adhesion of maple and spruce can be highly influenced by the nature of the plasma gas and the plasma treatment time. For example, in the case of sugar maple, coating adhesion increases by 66% after 1.5 s of exposure to argon plasma. Repetition of contact angle measurements one and two weeks after the plasma treatment further revealed that the plasma-induced modification is not permanent. Improvement of the wettability and adhesion were also obtained with the simpler and cheaper air plasmas, a very promising result for the development of advanced plasma reactors at atmospheric pressure specially designed for the wood industry.
Atmospheric-pressure plasmas; Sugar maple; Black spruce; Coating adhesion;
Water contact angle; Pull-off test