Effect of Boron Compounds on Properties of Chinese Fir Wood Treated with PMUF Resin

Plantation Chinese fir wood was modified by low molecular weight phenol melamine urea formaldehyde (PMUF) resin and boron compounds (BB) through a progressive gradual infiltration process. The results showed that the limiting oxygen index (LOI) values, density, dimensional stability and static flexural properties of the PMUF resin treated wood gradually improved with the increase of resin solid content. When boron compounds were additionally introduced into the PMUF resin, the density and the LOI values of the samples of compound modification increased, whereas the anti-swelling efficiency, the modulus of rupture and impact toughness decreased by more than 17.6%, 10.1% and 42.9%, respectively. It was demonstrated by X-ray diffraction and Fourier transform infrared spectroscopy that boron compounds could improve the crystallinity of resin modified samples and did not have a chemical reaction with resin or wood. Scanning electron microscope analysis indicated boron compounds made the microstructure of the resin polymers loose, influencing the mechanical properties and dimensional stability of resin modified wood.