Effects of plasma surface treatment on bending strength and modulus of elasticity of beech and poplar plywood

Cenk Demirkir,Ismail Aydin,Semra Colak,Hasan Ozturk

doi:10.4067/s0718-221x2017005000017

Cenk Demirkir, Ismail Aydin + Show 2 more

Open Access

https://doi.org/10.4067/s0718-221x2017005000017

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Abstract

This is a study on the effect of plasma treatment with different gases and plasma intensity on the bending strength and modulus of elasticity of plywood manufactured from beech and poplar. Oxygen (O2) and ammonia (NH3) plasma were applied on the veneer sheets; two plasma intensities were applied on the veneers with 150 and 300 W in the plasma chamber during one minute. Phenol formaldehyde resin was applied on one surfaces of each veneer with approx. 160 g/m2. Bending strength and modulus of elasticity were determined according to EN 310.The effects of plasma surface treatment on chemical structure of the panels were determined with FTIR-ATR analysis. Bending strength of all tested panels slightly and partly increased without statistical significance when applying oxygen plasma. The effect of ammonia plasma treatment on bending strength and was determined by the wood species and the plasma intensity, and it was not uniform. Modulus of elasticity of the panels with oxygen plasma treatment showed in most cases improvement, whereas ammonia plasma pretreated veneers caused lower values compared to the control panels.

Highlights

In recent years, the plasma modification process has been used to modify the surfaces of wood and wood based materials in order to enhance surface properties of the wood component and mechanical strength of the wood based materials (Aydin and Demirkir 2010, Acda et al 2012, Demirkir et al 2014).Plasma treatment is used to improve bonding properties of many materials such as wood based products by altering the surface properties and chemical structure of the wooden components
Ions, molecules, free radicals, electrons, and metastable species (Podgorski et al 2000).Different gas species can be used in plasmas in order to obtain the desired surface properties, by influencing the interactions between the gas and the solid surface depending upon the nature of the gas species used in plasma
The study reported here investigated the effect of plasma treatment with different gases and plasma intensity on the mechanical properties such as bending strength (MOR) and the modulus of elasticity (MOE) of plywood panels manufactured from different wood species

Summary

INTRODUCTION

The plasma modification process has been used to modify the surfaces of wood and wood based materials in order to enhance surface properties of the wood component and mechanical strength of the wood based materials (Aydin and Demirkir 2010, Acda et al 2012, Demirkir et al 2014).Plasma treatment is used to improve bonding properties of many materials such as wood based products by altering the surface properties and chemical structure of the wooden components. Literature contains some studies about the effects of plasma treatment with different gas species on adhesion properties (Wolkenhauer et al 2009), contact angle (Aydin and Demirkir 2010), wettability and bond. Acda et al (2012) stated that plasma modification results in to the formation of hydroxyl, carboxyl, aldehyde, and other polar functional groups effecting surface polarity These effects depend from gas species, and from the wood species used in the study reported here. It is hard to find a study describe the effects of plasma with different gas species and intensity on MOR and MOE of wood based materials from different wood species. The study reported here investigated the effect of plasma treatment with different gases and plasma intensity on the MOR and the MOE of plywood panels manufactured from different wood species

MATERIALS AND METHOD

RESULTS AND DISCUSSION

CONCLUSIONS