In-Situ Cross-Linking of Waterborne Epoxy Resin Inside Wood for Enhancing Its Dimensional Stability, Thermal Stability, and Decay Resistance

This paper describes the action mechanism of a waterborne epoxy resin (WEP) cross-linked inside wood and its influence on wood dimensional, thermal, and fungal stability. The WEP prepared by phase inversion was impregnated into wood under vacuum-pressure treatment, followed by in situ cross-linking upon heating to form a hydrophobic network inside wood porous structures. The weight gain and volume increment of the treated wood combined with the morphological observation indicated that the WEP components were able to penetrate into wood cell lumens as well as cell walls, cross-link, and finally fix stably inside them. The good fixation of the epoxy resin network formed in wood reduced the leaching into water. Results from Fourier transform infrared (FTIR) spectroscopy confirmed the reaction between the epoxy and wood. In addition, it was found that the dimensional stability, thermal stability, and decay resistance of wood were improved with the WEP modification. The scanning electron microscopy images clearly showed that brown-rot fungus caused more serious damage to the structure of wood than white-rot fungus.