Papers by Keyword: Poplar

Abstract: The poplar is largest plantation tree species of in China. However, poplar veneer is easily broken when subjected to drying for plywood. This work presents an orthogonal test to reveal the key technological parameters of poplar veneer with high moisture content (MC) on the bonding properties. The results showed that, veneer MC has a significant effect on internal bond (IB) and MC of obtained plywood, but has a light effect on the content of released formaldehyde. Resin content has a significant effect on IB, MC and content of released formaldehyde. Hot-press time has a significant effect on content of released formaldehyde; but has a light effect on MC and IB. The obtained optimal technological parameters of poplar veneer with high moisture content is, veneer MC of 26%, resin content of 11%, and hot-press time of 200s.

Abstract: In recent years the research on structure and efficiency mode of farmland shelterbelt are more, while the prediction models of the poplar are much less. The growth model is based on poplar growth and management, the development of information technology provides new methods for the research and evaluation of poplar growth model. All kinds of information technology are used to extract growth character parameters of poplar, and neural network and expert system is used to establish the relational models of the character parameters and production management of poplar, these models are used to provide the basis for the cultivation of poplar growth and management, which have important theory value and practical significance.

Abstract: The paper preheated poplar and Chinese fir with microwave before dipping into fire retardant solution with the purpose of improving their permeability. The test results showed that microwave increased the routs for liquid which proved to be a feasible way to facilitate fire retardant solution to enter into wood. Fire retardant loading dosage (FRLD) and implantation depth (ID) increased for both poplar and Chinese fir. Fire retardant properties such as oxygen index (OI), mass loss rate (MLR) and flame combustion time (FCT) increased and can meet the fire retardant wood requirements defined by standard of GA/T 42.1-92.

Abstract: This paper studied the differences of pulping performances, beating characteristics and strength properties between green liquor pretreatment-Kraft pulping and conventional Kraft pulping based on previous optimized pulping conditions. The green liquor pretreatment-Kraft pulping has higher yield, lower Kappa number, reduced residual effective alkali and decreased viscosity. Green liquor pretreatment improves pulp strength properties although green liquor pretreatment-Kraft pulp has beating characteristics similar to conventional Kraft pulp.

Abstract: Green liquor has lower hydroxide concentration and higher sulfidity, which makes it a better choice for modified alkali cooking. This paper studied process parameters of pretreatment stage on pulping properties of poplar green liquor pretreatment-Kraft pulping process. Conditional experiments with green liquor charge of 0.50L/kg, 0.75L/kg, 1.00L/kg and 1.25L/kg, maximum pretreatment temperature of 95°C, 105°C, 115°C and 135°C, and holding time of 30min, 60min and 90min, were carried out. The results shows that optimal pretreatment conditions are as follows: green liquor charge, 1.00L/kg; maximum pretreatment temperature, 115°C; holding time, 60min; and wood to liquor ratio, 1:4.

Abstract: Long fiber component of poplar CMP is modified by ozone to improve the paper physical performance in this paper. The condition of modification is studied by the orthogonal test method. The results show that the optimum conditions are: 2.5% ozone, pH 4,consistency 0.5%. The softness, length, swelling properties and hydrophilcity of long fibers are improved after modification. The crystallinity of fiber is improved and the lignin content is reduced. The better performance in tear index and tensile index was attained compared with unmodified CMP holo-pulp to some extent: tensile index increased from 35.8N·m·g^-1 to 44.6N·m·g^-1, tear index increased from 4.58 mN·m²·g^-1 to 8.16 mN·m²·g^-1, brightness had a slightly increase.

Abstract: Through impregnation with UF and PF resin, the modification technology of Poplar was experimented and studied. The study results showed that WPG(weight percent gain) of the test-pieces impregnated with UF and PF resin had less difference. The wood vessels were scarcely filled by resin especially UF resin. Regardless of impregnating with UF or PF resin, the cell lumens near the veneer junctions are basically filled by the resin. But the most of the cell lumens depart farther from the veneer junctions were only filled by PF resin instead of UF resin.

Abstract: Aimed to improve the properties of Poplar, this study, taking phenol-formaldehyde resin (PF) and urea-formaldehyde resin (UF) as impregnation resin, probed the effect of the technology factors-vacuum time, solid content of resin, impregnation temperature and time on the impregnation results of Poplar, and the relationship between the resin and the wood was researched through infrared spectrum. The weight percent gain (WPG) of test-pieces increased with vacuum time extending, and WPG of the test-pieces were greatest when the solid content of resin was 30%, and the impregnation temperature was 25-30°C. when the impregnation time extended from 3 h to 9 h, WPG of the test-pieces presented increase trend which wasnt obvious. In this wood impregnated resin, the reaction between the resin and the hydroxy in wood formed ether bond binding, which proved that the resin and the wood occurred the chemical reaction.

Abstract: In this paper, the poplar Alkaline Peroxide Mechanical Pulp (APMP) pulping wastewater was treated by the SBR. The pulping wastewater was from the processes of washing, soaking and defibrination. The COD of the pulping wastewater was 5671 mg/L and the BOD was 1862 mg/L. The B/C (biological oxygen demand/chemical oxygen demand) ratio of the pulping wastewater was 0.32, which indicated that the wastewater was suitable to be treated by biological methods. SBR technology was used to treat the pulping wastewater. After a series of experiments, the best conditions for the pulping wastewater was achieved as follows: time 6hrs, original pH about 8. Under these conditions the removal ratio of COD can reach 81.4% and that of BOD can reach 91.5%;but the removal ratio of the TSS and the Chromaticity were low, the removal ratio of TSS only reach 31.8%.

Abstract: In order to achieve the quantification analysis and visualization of poplar morphology, the technology framework of poplar simulation based on growth model is made. The paper carries out data collection and field observation, then the morphological structure parameters and knowledge models which can describe different poplar varieties are constructed, in the framework of the poplar growth models we integrate poplar morphological knowledge models and geometric models based on morphological character parameters, make the growth model of poplar can output morphological character parameters and topological structure, and further perform the geometric model reconstruction of poplar growth simulation. Practice has proved that the construction of growth models of poplar can simulate the poplar growth at different growth stages, and provide new ideas and means for growth simulation research of poplar morphology structure.