Change search
ReferencesLink to record
Permanent link

Direct link
Comparing bond strength and water resistance of alkali-modified soy protein isolate and wheat gluten adhesives
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.ORCID iD: 0000-0002-8348-2273
2010 (English)In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 30, no 2, 72-79 p.Article in journal (Refereed) Published
Abstract [en]

The tensile strength of beech substrates bonded with dispersions of alkali-denatured soy protein isolate (SPI) and wheat gluten (WG) was measured for comparison of bond strength and resistance to cold water. The proteins were denatured with 0.1M NaOH (pH 13). Dispersions with different protein concentration and viscosity were investigated. The adhesive properties were studied at different press temperatures (90, 110, and 130 degrees C) and press times (5,15, and 25 min). Two types of application methods were used in order to overcome the problem with different viscosity of the dispersions. In addition, SPI was denatured at two different pH levels (approximately 10 and 13) and with two different concentrations of salt (158 mu M and 0.1 M), in order to compensate for the different isoelectric points of the proteins. The adhesive properties of WG powder with different particle sizes were also compared. The tensile strengths of the wood Substrates were measured according to somewhat simplified versions of the European Standards EN 204 and EN 205. The bond lines were studied with light microscopy. The results indicate that the adhesive properties of SPI are superior, particularly with regard to water resistance. However, the water resistance of WG was to some extent improved when starved adhesive joints could be avoided. Similar tensile strength values were obtained for the dispersions of alkali-denatured SPI regardless of pH or salt concentration. No apparent difference in adhesive strength was observed for the WG dispersions from powder with different particle sizes.

Place, publisher, year, edition, pages
2010. Vol. 30, no 2, 72-79 p.
Keyword [en]
Adhesives for wood, Novel adhesives, Wood, Mechanical properties of, adhesives, Plant protein
National Category
Chemical Sciences
URN: urn:nbn:se:kth:diva-19163DOI: 10.1016/j.ijadhadh.2009.09.002ISI: 000274078200003ScopusID: 2-s2.0-71949084148OAI: diva2:337210
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2012-05-14Bibliographically approved
In thesis
1. Exploring the Wood Adhesive Performance of Wheat Gluten
Open this publication in new window or tab >>Exploring the Wood Adhesive Performance of Wheat Gluten
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The increasing environmental concern has reawakened an interest in materials based on renewable resources as replacement for petroleum-based materials. The main objective of this thesis was to explore plant proteins, more specifically wheat gluten, as a binder in wood adhesives intended for typical solid wood applications such as furniture and flooring.

Alkaline and acidic dispersions of wheat gluten were used as wood adhesives to bond together beech wood substrates. Soy protein isolate was used as a reference. The tensile shear strengths of the substrates were measured for comparison of bond strength and resistance to cold water. AFM in colloidal probe mode was used to investigate nanoscale adhesion between cellulose and protein films. Wheat gluten was divided into the two protein classes; glutenins and gliadins, and their adhesive performance was compared with that of wheat gluten. Heat treatment and mild hydrolysis were investigated as means for improving bonding performance of wheat gluten. The treated wheat gluten samples were analysed by SE-HPLC and 13C-NMR to correlate molecular size distribution and structural changes with bonding performance.

Soy protein isolate is superior to wheat gluten, especially in regards to water resistance. However, the bond strength of wheat gluten is improved when starved bond lines are avoided. The AFM analysis reveals higher interfacial adhesion between soy protein isolate and cellulose than between wheat gluten and cellulose. These results partly explain some of the differences in bonding performance between the plant proteins. Soy protein isolate contains more polar amino acid residues than wheat gluten and possibly interacts more strongly with cellulose. Furthermore, the bond performances of wheat gluten and glutenin are similar, while that of gliadin is inferior to the others, especially regarding water resistance. The extent of penetration of the dispersions into the wood material has a large impact on the results. The bonding performance of gliadin is similar to the others when over-penetration of the dispersion into the wood material is avoided. Moreover, the bond strength of the wheat gluten samples heated at 90°C was in general improved compared to that of wheat gluten. A small improvement was also obtained for some of the hydrolyzed wheat gluten samples (degree of hydrolysis: 0-0.6 %). The improvements in bonding performance for the heat treated samples are due to polymerization, while the improvements for the hydrolyzed samples are due to denaturation. The 13C-NMR analysis of the treated samples confirms some degree of denaturation.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. 74 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2012:23
plant protein, wood adhesive, mechanical properties, wheat gluten, soy protein isolate, gliadin, glutenin, adhesion, hydrolysis, heat treatment, AFM
National Category
Polymer Technologies
urn:nbn:se:kth:diva-94883 (URN)978-91-7501-348-0 (ISBN)
Public defence
2012-06-01, Sal K2, Teknikringen 28, KTH, Stockholm, 10:00 (English)
QC 20120514Available from: 2012-05-14 Created: 2012-05-11 Last updated: 2012-05-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Nordqvist, PetraMalmström, Eva
By organisation
Coating Technology
In the same journal
International Journal of Adhesion and Adhesives
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 147 hits
ReferencesLink to record
Permanent link

Direct link