Optimized Reconstructed Technology Of Bamboo-Eucalyptus Composites

China is a country with short of forestry resources; whether the forest coverage rate or per capita is lower than those of the world's average, especially lack of larger-sized softwood and high quality hardwood. Fortunately, China has plenty of bamboo resources and forest plantation, the planting area and production of which rank first in the world. So there will be a significance to use those resources with efficiency and reasonability. The Moso bamboo (Phyllostachys pubescens Mazel exH.de Lebaie) and Eucalyptus (E.urophylla) abundant in the south of China, were choused as experimental materials in this dissertation. Based on the discussion of the basic physical and mechanical properties, surface wettability of bamboo and Eucalyptus, bonding properties and the mat thermal conductivity, the dissertation optimized the technique of reconstruction for bamboo-Eucalyptus composites in structure and technology. The main conclusions obtained from the research and analysis is as follows:The effect of thickness of bamboo strips on the basic physical and mechanical properties are not significant, while the effect of thickness of eucalyptus veneer strips are very obvious, with the increase of thickness, the physical and mechanical properties decrease. The physical and mechanical properties of eucalyptus veneer strips are improved by treated with glue-spreading and hot-pressing, the improving degrees of the physical and mechanical properties are different depending on veneer thickness, glue-spread and density.The environmental temperature has a significant impact on the wettability of PF on the surface of bamboo and Eucalyptus, the wettability of the PF on the surface of bamboo and decreased with increasing of the temperature from 20℃to 100℃; stacking time of Eucalyptus veneer after peeling is of a great effect on the wettability on the surface of eucalyptus veneer, the wettability on the surface of eucalyptus decreased with the extension of storage time. Ball-milling can improve the wettability, penetration and spreading performance of eucalyptus veneer by certain extent.The systems for evaluating the bonding strength distribution were established in this paper. Two-tailed test P value of bonding strength of plywood made from plantation wood such as eucalyptus, polar and larch is 0.203,0.235and 0.464, respectively, more than significance level of 0.05. They are approximate conform to the normal distribution on the whole, however there is a certain deviation as it is asymmetric with positive bias; the bonding strength of eucalyptus and poplar plywood turned out to be leptokurtosis while larch plywood's is platykurtic.A mathematical model of the hot-pressing temperature curve was established in this paper based on the studies of hot-pressing temperature curve of bamboo and eucalyptus laminated veneer lumber. The R²-value of the theoretical curve and the actual curve are above 0.92. The coefficient of hot-pressing temperature rate(k-value) has a linear relation with mat layers, hot-pressing temperature, hot-pressing pressure and water content, the thermal conductivity of bamboo and eucalyptus composites can be improved by adjusting mat's structure and hot-pressing process.The stiffness prediction model suitable for bamboo-wood composites was established in this paper. The correlation coefficient R2-value of predicted and experimental value of MOE eucalyptus-bamboo composites are above 0.80, the error between experimental value and predicted value is within 11% by taking MOE of bamboo LVL and eucalyptus LVL as a basic data for properties' design of bamboo-eucalyptus composites, therefore, the model has a great practical significance.Based on the studies of the failure mechanisms of bamboo-wood composites, a qualitative mathematical prediction model of bamboo-wood composites strength was established in this paper, which can qualitatively interpret different failure types of bamboo-eucalyptus composites. The dissertation explained the design rules of bamboo-eucalyptus composites in theory by using stiffness prediction models, strength models and material fracture theories.The preferable optimum hot-pressing process for 13-layers LVL with 2.25 mm thickness veneer is as below: temperature is 140℃, hot-pressing time is 1min·mm^-1, glue spread is 250g·m², compression rate is 16%。...