UV Irradiation of Wood Surface: Bonding Properties

Various surface modification techniques have been developed to improve synthetic polymer surfaces’ wetting, adhesion, and printing by adding various functional (polar) groups. UV irradiation has been proposed as a suitable procedure to achieve adequate surface modifications of such polymers, which c...

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Main Authors: Tomislav Gržan, Lucianna Grieco, Vjekoslav Živković, Goran Mihulja
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Polymers
Subjects:
Online Access:https://www.mdpi.com/2073-4360/15/11/2552
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author Tomislav Gržan
Lucianna Grieco
Vjekoslav Živković
Goran Mihulja
author_facet Tomislav Gržan
Lucianna Grieco
Vjekoslav Živković
Goran Mihulja
author_sort Tomislav Gržan
collection DOAJ
description Various surface modification techniques have been developed to improve synthetic polymer surfaces’ wetting, adhesion, and printing by adding various functional (polar) groups. UV irradiation has been proposed as a suitable procedure to achieve adequate surface modifications of such polymers, which can be of further use to bond many compounds of interest. The activation of the surface, the favourable wetting properties, and the increased micro tensile strength of the substrate after short-term UV irradiation suggest that such pretreatment can also improve the bonding of the wood-glue system. Thus, this study aims to determine the feasibility of UV irradiation for pretreatment of wood surfaces before gluing and to determine the properties of wooden glued joints prepared in this way. UV irradiation was used to modify variously machined pieces of beech wood (<i>Fagus sylvatica</i> L.) before gluing. Six sets of samples were prepared for each machining process. Samples prepared in this manner were exposed to irradiation on a UV line. Each radiation level had a certain number of passes through the UV line, the more passes, the stronger the irradiation. Thus, the radiation levels were as follows: 1, 5, 10, 20, and 50 passes. The dose (energy delivered on the wood surface) in one pass was 2.36 J/cm<sup>2</sup>. A wetting angle test with glue, a compressive shear strength test of lap joints, and designation of main failure patterns were used to evaluate the properties of wooden glued joints. Wetting angle test was performed according to EN 828, while the compressive shear strength test samples were prepared and tested following the ISO 6238 standard. The tests were conducted using a polyvinyl acetate adhesive. The study found that UV irradiation before gluing improved the bonding properties of variously machined wood.
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spelling doaj.art-931659b3e77a42f29b7821a62e02dbec2023-11-18T08:27:04ZengMDPI AGPolymers2073-43602023-05-011511255210.3390/polym15112552UV Irradiation of Wood Surface: Bonding PropertiesTomislav Gržan0Lucianna Grieco1Vjekoslav Živković2Goran Mihulja3Faculty of Forestry and Wood Technology, University of Zagreb, 10000 Zagreb, CroatiaSchool of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, 85100 Potenza, ItalyFaculty of Forestry and Wood Technology, University of Zagreb, 10000 Zagreb, CroatiaFaculty of Forestry and Wood Technology, University of Zagreb, 10000 Zagreb, CroatiaVarious surface modification techniques have been developed to improve synthetic polymer surfaces’ wetting, adhesion, and printing by adding various functional (polar) groups. UV irradiation has been proposed as a suitable procedure to achieve adequate surface modifications of such polymers, which can be of further use to bond many compounds of interest. The activation of the surface, the favourable wetting properties, and the increased micro tensile strength of the substrate after short-term UV irradiation suggest that such pretreatment can also improve the bonding of the wood-glue system. Thus, this study aims to determine the feasibility of UV irradiation for pretreatment of wood surfaces before gluing and to determine the properties of wooden glued joints prepared in this way. UV irradiation was used to modify variously machined pieces of beech wood (<i>Fagus sylvatica</i> L.) before gluing. Six sets of samples were prepared for each machining process. Samples prepared in this manner were exposed to irradiation on a UV line. Each radiation level had a certain number of passes through the UV line, the more passes, the stronger the irradiation. Thus, the radiation levels were as follows: 1, 5, 10, 20, and 50 passes. The dose (energy delivered on the wood surface) in one pass was 2.36 J/cm<sup>2</sup>. A wetting angle test with glue, a compressive shear strength test of lap joints, and designation of main failure patterns were used to evaluate the properties of wooden glued joints. Wetting angle test was performed according to EN 828, while the compressive shear strength test samples were prepared and tested following the ISO 6238 standard. The tests were conducted using a polyvinyl acetate adhesive. The study found that UV irradiation before gluing improved the bonding properties of variously machined wood.https://www.mdpi.com/2073-4360/15/11/2552UV lightUV irradiationmachiningsurface modificationbonding properties
spellingShingle Tomislav Gržan
Lucianna Grieco
Vjekoslav Živković
Goran Mihulja
UV Irradiation of Wood Surface: Bonding Properties
Polymers
UV light
UV irradiation
machining
surface modification
bonding properties
title UV Irradiation of Wood Surface: Bonding Properties
title_full UV Irradiation of Wood Surface: Bonding Properties
title_fullStr UV Irradiation of Wood Surface: Bonding Properties
title_full_unstemmed UV Irradiation of Wood Surface: Bonding Properties
title_short UV Irradiation of Wood Surface: Bonding Properties
title_sort uv irradiation of wood surface bonding properties
topic UV light
UV irradiation
machining
surface modification
bonding properties
url https://www.mdpi.com/2073-4360/15/11/2552
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