The Mechanical Strength And Interface Properties Of DMDHEU-modified Wood

In the paper, it is discussed that wood is modified by DMDHEU. The dimensional stability, mechanical strength and interface strength of DMDHEU-modified wood were explored and the mechanism of DMDHEU modification was discussed.In the research,30%DMDHEU resin was used to modify wood catalyzed with1.5%,3%citric acid or1.5%MgC2l·6H2O, respectively. And then the wet modified wood was heated under60℃、90℃、120℃、and150℃. The weight percentage gain of modified wood changed regularly with temperature raising. Before leaching, the weight percentage gain of modified wood decreased with temperature rising. After leaching, the weight percentage gain of modified wood increased with temperature rising. The dimensional stability of DMDHEU-modified wood increased with temperature rising. The kinds and concentration of catalyst had slight influence on the dimensional stability of modified wood. The mechanical strength of modified wood increased firstly and than decreased with temperature rising. And the strength of modified wood treated under90℃and120℃did not decrease comparing the control, in the contrast, it was increased. The kinds and concentration of catalyst had slight influence on the strength of modified wood. The wettability of DMDHEU-modified wood was worse than the control’s. The interface strength of DMDHEU-modified treated under90℃was higher than that under120℃. Besides, the interface strength of post-DMDHEU-modification wood was better than that of pre-DMDHEU-modification wood.Based on the results of researches, the mechanism of DMDHEU modification for wood was explored by FTIR, SEM, TG and XPS in order to explain why the dimensional stability is better. And the pore size of modified wood cell wall was examined by DSC through Gibbs-Thomson equation to clarify the trend of mechanical strength and interface strength of DMDHEU-modified wood.