Papers by Author: Ding Guo Zhou

Abstract: The waxy wheat straw surface and high SiO₂ content of wheat straw agrifibres make wheat straw-based panel production much more difficult than traditional wood-based panel manufacture. Plasma surface modification is regarded as one of the cost effective surface treatment techniques for many materials including natural fibers. In this study, plasma technique was employed to treat the surface of wheat straw. After the plasma treatment, the surface properties were then evaluated by determining the contact angles of 3 liquids on the wheat straw surface and by analysis using Fourier Transform Infrared Spectroscopy (FTIR).The results showed that the contact angles of water, glycerol, and UF resin after the plasma treatment decreased by 44.1%, 18.6%, and 24.9%, respectively. In the meantime, –OH, and -C=O groups increased according to the FTIR analysis. The FTIR analysis also indicated a significant SiO₂ reduction in the plasma treated wheat straw. Obviously, the plasma treatment improved the wettability of wheat straw, increased the numbers of oxygen-containing functional groups, and also removed the weak interface of wheat straw remarkably. By means of the plasma treatment, the internal bond property between modified wheat straw fibers was expected to enhance, and thus some cheaper traditional adhesives such as urea formaldehyde (UF) and phenol formaldehyde (PF) can be used for the wheat straw-based panel production instead of using expensive Diphenylmethane Diisocyanate (MDI).

Abstract: In this study, rice straw (Oryza sativa L.) fibril and fibril aggregates (RSFs) material isolated by high intensity ultrasonication (HIUS) was used as reinforcement in an RSFs/Polypropylene (PP) nanocomposites. The morphology of RSFs was investigated by scanning electron microscopy (SEM). The mechanical properties were evaluated by tensile test. The fourier transform infrared spectroscopy (FTIR) test was also performed to investigate the interface compatibility between RSFs and PP matrix. Results indicated that the tensile strength of RSFs/PP nanocomposites increased with increasing cycle time of extruder from 10 min to 30 min at 180°C. The maximum value of tensile strength was 31.2 MPa appeared at the conditions of 190°C and cycle 20 min. The elastic modulus increased by adding 5 wt% RSFs into the PP/MAPP matrix. However, there was no distinct difference of elongation in RSFs/PP nanocomposites at different extruder conditions. The RSFs embedded into the PP/MAPP matrix and exhibited better interaction by FTIR test.

Abstract: Castor is one kind of excellent woody materials and can be used to make wood based panel instead of the wood materials. To use the castor stalk better, it studies the chemical composition including cellulose, hemicellulose and lignin by high performance liquid chromatograph (HPLC) and the standard of PRC respectively, the pyrogenation-characters by thermo gravimetric analyzer (TGA) and the relationship between chemical composition and the pyrogenation-characters by SAS. The results showed that the chemical composition and pyrogenation-characters are different in different layers of the castor stalk, besides the castor stalk is mainly pyrolysis in second stage (between 170-330°C).

Abstract: Castor- stalk is one kind of excellent wood materials can be used to make the wood based panel and substitute for the wood resource, reducing the pollution caused by castor stalk-burnt. The properties of the castor stalk based fiber panel are better than the properties of the castor stalk based particle panel made under the same techniques. It studied the infiltrating-characters, the radicals-concentration and the micro-structure of the castor stalk based panel with highly effective surface tension and angle of contact instrument, Electron spin resonating spectrum instrument (ESR) and Scanning electronic microscope (SEM). The results show that the wetting-soakage and the radicals-concentration of the castor fiber are worse than those of the castor particle. The micro-structure of the castor fiber is complete and smooth without crevasse in the castor stalk based fiber panel. But the micro-structure of the castor fiber is not complete and is bruised in the castor stalk based particle panel. So it show that the properties of the castor stalk based particle board are worse than those of the castor stalk based fiber board caused by the micro-structure changed maybe.

Abstract: Castor stalk is one of excellent woody materials.which is the byproduct of the castor oil plant. Itwas usually burnt without use at all when the castor seed were harvest. To use this resource, we studied the castor stalk based panel made with different resin including UF, PF and MDI resin. The results show that the properties of castor stalk based particle panel made with UF and MDI resin by certain techniques can reach the requirement of the standard of China expect the castor stalk based particle board with PF resin which will be studied further more.

Abstract: Castor-oil stalk is one kind of excellent woody materials, and the thickness swelling ( TS ) of the castor-oil stalk based panel with Urea- formaldehyde resin ( UF ) cannot meet the requirement of the Standard of People’s Republic of China. the TS of the panel was improved with wax emulsion.Results showed that the mechanical properties and the TS of the particle panels were improved as the wax emulsion loading increased. The TS of castor stalk based particle boards and fiber boards can meet the requirement of standard of PRC when 1.44 and 1.2 wt% wax emulsion, respectively, was added.