Papers by Author: Xiao Dong Zhu

Abstract: The influence of hot-pressing parameters on formaldehyde and other volatile organic compounds (VOC) were studied in this paper. The particleboard of larix gmelinii and UF resin were used as main raw materials. Orthogonal design was adopted to analyze the influence of hot-pressing temperature, time, resin and density on the concentration of formaldehyde and other VOC. The results showed that the emission of formaldehyde and other VOC were significantly affected by hot-pressing temperature, time, resin and density. The emission of formaldehyde and other VOC were obviously decreased in usage with the increasing of hot-pressing temperature, press time and the decreasing of density. Taking formaldehyde and other VOC emission into account, the optimized condition was hot-pressing temperature of 180°C, press time of 5 min, resin content of 11%, board density of 0.6g/cm³. The emissions of optimized particleboard satisfied the national standard GB18580-2001.

Abstract: This paper explored the effect of MDI, UF and FRW content on the mechanical and fire retardant property of straw based panels with surface alkali liquor processing. In order to manufacture the straw based panel with high quality, low toxic and fire retardant, the interface of wheat-straw was treated with alkaline liquid under the optimal treating condition: alkaline liquid concentration was 0.4-0.8%, alkaline dosage was 1:2.5-1:4.5, alkaline-treated time was 12h-48h.The physical and mechanical properties of wheat-straw boards after treated could satisfy the China national standard. And the variance analysis of the fire retardant property of straw based panel showed that TTI, pkHRR and peak value appearance time were not affected by the MDI, UF and FRW content significantly. The results of orthogonal test showed that the optimized processing condition was MDI content as 4%, UF resin content as 7% and the FRW content as 10%.

Abstract: The purpose of this study is to reveal the concentration variations of VOC concentrations of larch particleboards with different processing parameters. The mat moisture content (MC), panel type and density were chosen as the influencing factors to investigate the VOC emissions after processing, and consequently provide basic guideline for the selection of processing parameters of particleboards to control the pollutants. 1m³ environmental chamber and portable VOC monitor were used for VOC sampling and analysis. The results showed that these factors had significant impact on VOC concentrations. The increase of MC, board panel and density had a positive effect on VOC emissions. With the MC and board density various in the ranges from 6%-14% and 0.60-0.80 g·cm^-3, the TVOC concentrations increased 42.6% and 74.7% separately. The three layers particleboard had the higher concentration than the single layer particleboard.

Abstract: Three mixed liquids, Styrene, Methylmethacrylate and Vinyl acetate were used to soak poplar veneer to obtain strengthen poplar veneers. The optimal molar ratio was fixed on 1:2:1.Soaking and polymerization technology were obtained as pressure 0.4Mpa, packing time 60 minutes, polymerization temperature 80°C, polymerization time 6 hours, cobalt naphthenate 2%, zinc chloride 6%, and azobisisobutyronitrile 3%. The impact of high temperature on the conversion was significant in the chosen level, other factors on the conversion rate was not significant.

Abstract: The wheat straw was pretreated using heat-treatment and water action and then diversified flat weave experiments were performed. Effects of the technology of knitting (including machinery spinning method, sewing spelling method, weaving process of "picks one pressures one" and "picks two pressures two") on veneer material quality and technology of decorative facing was investigated. The results show that both of sewing spelling method and weaving process of "pick two pressure two" achieve better effect with close construction, level, nice appearance and simple to weave. Experiments for optimizing the technology were performed by using non-woven fabric as the laminated veneer materials, The optimal technical parameters when using non-woven fabric were as follows: MDI 1.5％ and UF 8％ with the dosage of 50-80g/m2; temperature of 85-105°C; pressure of 0.2-0.5 MPa; time of 25min(10 sheet at a time).

Abstract: A new kind of bio-based composite panel with veneer material and performance of decorative material was produced by process of dissection, staining, weaving and collage. The bio-based composite panel was instructed with art design using the wheat straw as raw material. The facing technology of the bio-based composite panel with wheat straw veneer material was investigated and no previous research using pretreated wheat straw to produce the veneer material with characteristic of decorative function. The bonding strength was measured and it reached 0.75 MPa. It is demonstrated that pretreated wheat straw can be used for furniture manufacturing and decorative applications directly.

Abstract: Particleboard has been indicated as one possible source of volatile organic compounds (VOCs) at normal indoor. This paper examines the VOCs emissions from the larch particleboards. Temperature, relative humidity and air change rate are significant factors influencing the VOCs emissions from particleboards. With the temperature and humidity various in the ranges from 23°C-40°C and 10%-70%RH the TVOC concentrations increased. Whereas the increasing of air change rate causes the TVOC concentration decreased.

Abstract: The removal efficiencies of 4 air-cleaning materials on formaldehyde and VOC emissions from particleboards were examined in this paper. The effect of activated carbon and photo catalyst on formaldehyde and VOC emissions removal was notable in short time. The effect of scavenger was obviously on formaldehyde removal for its synthetic mechanism. And the impact of bioenzyme on formaldehyde and VOC emissions from particleboards is dependent on the test conditions and it shows no impact on emissions in this experiment.

Abstract: This article introduces the fractal theory and its applications in wood fracture、wood texture、wood drying 、wood defect nondestructive detecting and other fields in wood science researching, among which many researching results are characterised by fractal dimension. While the methods in other fields which fractal were used in their researches were refered , the writer attempts to apply them in wood science researches.At last the new viewpoints and its applications were proposed.

Abstract: The orthogonal theories were carried out to analyze the effect of MDI, UF and FRW content on the mechanical and fire retardant properties of rice-straw based boards in this paper. The interface alkaline treatment showed a significant effect on the surface bonding performance of rice- straw. The bonding property of rice-straw based boards increased with the increasing of resin content, especially for the effect of MDI content on MOR, MOE. The tendency of pkHRR decreased and the target for fire retardant realized by the FRW content increased. Based on analysis, the optimal technical parameters were obtained as MDI content 3%, UF content 6% and FRW fire retardant 10% separately.