The Application of Oak Bark Powder as a Filler for Melamine-Urea-Formaldehyde Adhesive in Plywood Manufacturing

Radosław Mirski,Dorota Dziurka,Jakub Kawalerczyk,Joanna Siuda,Marek Wieruszewski

doi:10.3390/f11121249

Abstract

The woodworking industry generates a great amount of bark which has not yet found a wider industrial application. None of the previously conducted research has considered oak bark application (which is one of the most often processed wood species in Poland) as a filler for wood adhesives. Moreover, no studies have determined the properties of bark containing melamine-urea-formaldehyde resin (MUF), which increasingly replaces pure urea-formaldehyde adhesives. Thus, the aim of the study was to determine the possibility of grinded oak bark application as a filler for MUF adhesive in plywood manufacturing. The chemical composition of oak bark was evaluated. Properties of liquid resins, such as viscosity, gel time, pH, and solid content, were determined. Chemical interaction between the filler and resin was assessed with using Fourier-transform infrared (FTIR) spectroscopy. Plywood panels manufactured using MUF adhesive filled with different bark concentrations (10%, 15%, 20%, 25%) were tested in terms of such properties as formaldehyde release and bonding quality. Studies have shown an improvement in liquid resin properties. The course of FTIR spectra did not explain the chemical interaction between the polymer and the filler. The addition of oak bark at a concentration of 15% made it possible to produce plywood panels characterized by reduced formaldehyde release and improved bonding quality.

Highlights

The compositions of adhesive mixtures in plywood production must contain proper additives, usually called fillers or extenders [1]
Despite a number of studies concerning the use of bark as a filler for UF, phenol-formaldehyde resin (PF), and Polymeric diphenylmethane diisocynate (pMDI) adhesives, no studies have examined the effect on the properties of melamine-urea-formaldehyde resin (MUF) bond lines in plywood manufacturing
The aim of the current study was to investigate the effect of the addition of oak bark particles to MUF resin on the properties of manufactured plywood

Summary

Introduction

The compositions of adhesive mixtures in plywood production must contain proper additives, usually called fillers or extenders [1]. The more water is absorbed by the bark particles, the less water can penetrate the veneer The addition of a proper amount of bark resulted in the possibility of obtaining plywood panels characterized by good mechanical properties and bonding quality exceeding the value required by the standard. Studied the effect of benuang (Octomeles sumatrana BN) and duabanga (Duabanga moluccana DB) barks as the filler for phenol-formaldehyde resin (PF) in glulam production. Despite a number of studies concerning the use of bark as a filler for UF, PF, and pMDI adhesives, no studies have examined the effect on the properties of MUF bond lines in plywood manufacturing. The aim of the current study was to investigate the effect of the addition of oak bark particles to MUF resin on the properties of manufactured plywood

Materials

Methods

Results and Discussion

Conclusions