We explored the discoloration of rattan cane using X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). XPS analysis showed that after the cane was stained by Lasiodiplodia theobrom...We explored the discoloration of rattan cane using X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). XPS analysis showed that after the cane was stained by Lasiodiplodia theobromae, carbon and oxygen elements and the ratio of oxygen to carbon decreased. Considering atomic binding,C_1 and C_4 contents increased, while C_2 and C_3 contents decreased, and the ratio of O_2 to O_1 decreased sharply. The relative contents of lignin, cellulose and polysaccharides increased and new substances with low O_2/O_1 ratio occurred. FTIR analysis showed that the absorption peaks of O–H at 3346 cm^(-1), aliphatic C–H at 2921, 2853 and1464 cm^(-1), and C=O at 1723 cm^(-1), were characteristic peaks of fungal melanin intensified, indicating that cane discoloration was primarily caused by fungal melanin. The absorption peaks characterizing cellulose and lignin like polysaccharides at 800 cm^(-1), C–H at 1374 cm^(-1), C–O at1058 and 1038 cm^(-1), phenolic hydroxyl at 1245 cm^(-1),aromatic ether bonds at 1270 cm^(-1), carbon skeleton at1608 cm^(-1) and benzene ring at 1500 cm^(-1) were enhanced since the fungus mainly consumed the extractives in cane cell lumens and the main composition content increased relatively. Regardless of the discoloration caused by natural fungi or inoculated fungi, the discoloring feature and composition changes were identical except that the fungusinoculated cane had more melanin.展开更多
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 limit...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.展开更多
基金supported by the National Key Project of S&T Supporting Programs Funded by MOST of China during the 12th Five-year Plan(No.2012BAD23B0104)
文摘We explored the discoloration of rattan cane using X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). XPS analysis showed that after the cane was stained by Lasiodiplodia theobromae, carbon and oxygen elements and the ratio of oxygen to carbon decreased. Considering atomic binding,C_1 and C_4 contents increased, while C_2 and C_3 contents decreased, and the ratio of O_2 to O_1 decreased sharply. The relative contents of lignin, cellulose and polysaccharides increased and new substances with low O_2/O_1 ratio occurred. FTIR analysis showed that the absorption peaks of O–H at 3346 cm^(-1), aliphatic C–H at 2921, 2853 and1464 cm^(-1), and C=O at 1723 cm^(-1), were characteristic peaks of fungal melanin intensified, indicating that cane discoloration was primarily caused by fungal melanin. The absorption peaks characterizing cellulose and lignin like polysaccharides at 800 cm^(-1), C–H at 1374 cm^(-1), C–O at1058 and 1038 cm^(-1), phenolic hydroxyl at 1245 cm^(-1),aromatic ether bonds at 1270 cm^(-1), carbon skeleton at1608 cm^(-1) and benzene ring at 1500 cm^(-1) were enhanced since the fungus mainly consumed the extractives in cane cell lumens and the main composition content increased relatively. Regardless of the discoloration caused by natural fungi or inoculated fungi, the discoloring feature and composition changes were identical except that the fungusinoculated cane had more melanin.
基金12th Five-Year Key Technology R&D Program of China(No.2015BAD14B01)for their financial support of this research.
文摘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.
