Increasing the Strength of the Glue Line in the Production of Thermally Modified Wood Paneling

Ruslan Rushanovich Safin,Albina Safina,Shamil Mukhametzyanov,Ruslan Khasanshin,Aigul Ravilevna Shaikhutdinova

doi:10.3390/coatings11020253

Ruslan Rushanovich Safin, Albina Safina + Show 3 more

Open Access

https://doi.org/10.3390/coatings11020253

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Journal: Coatings	Publication Date: Feb 20, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Kazan State Technological University

Abstract

This work is devoted to the study of the effect of ultraviolet rays for the surface activation of pine wood thermally modified at temperatures of 180−240 °C in order to increase the surface roughness, enhance the wettability of thermal wood and the adhesive strength of the glue in the production of wood block furniture panels. Studies were carried out to measure the contact angle of wettability of thermally modified wood samples of pine, as a result of which it was determined that the ultraviolet treatment process contributes to an increase in the adhesion properties of the surface layer of thermally modified wood by more than 13% due to the reactivity of ultraviolet rays to oxidize and degrade ligno-containing wood products. At the same time, the most active process of surface activation takes place during 60 min of ultraviolet irradiation of wood with a total irradiation of at least 125 W/cm2. It was revealed that the combined effect of two-stage wood processing, including preliminary volumetric thermal modification followed by surface ultraviolet treatment, causes an increase in the moisture resistance of glued wood products by 24%. So, if the strength of the glue seam when gluing natural wood samples after boiling decreased by 46%, then the samples that underwent two-stage processing showed a decrease only by 22%. In connection with the results obtained, an improved technology for the production of furniture boards for the manufacture of moisture-resistant wood products is proposed.

Highlights

IntroductionDue to the combination of such unique natural properties as availability, ease of processing and chemical resistance has found wide application in a variety of areas and spheres of human life
We evaluate the possibility of UV exposure to activate thermally modified pine wood to increase surface roughness, enhance wettability of thermally modified wood (TMW) and adhesive strength of the glue in the production of wood block furniture panels
As a result of the research, it was revealed that the thermal modification of wood affects the decrease in adhesion, which can be explained by the deterioration of the wettability of the thermo wood, while the ultraviolet irradiation of thermally modified wood increases the adhesion strength of the binder to the surface of the material

Summary

Introduction

Due to the combination of such unique natural properties as availability, ease of processing and chemical resistance has found wide application in a variety of areas and spheres of human life. Wood as a structural material, as well as filler in composite materials, is not without drawbacks, which include significant volumetric moisture deformations, the development of swelling pressure, pronounced anisotropy and water absorption [1,2]. Hygroscopicity and wettability should be attributed to the physical properties of wood, which have a significant effect on the development of the listed disadvantages. Various methods of chemical modification are used to eliminate the existing shortcomings of wood, they are not devoid of a negative effect: the strength of the treated wood decreases, the processed material does not adhere well, and its toxicity increases [3,4,5]

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