Moso Bamboo/Chinese Fir Laminated Composite And Its Properties

The Moso bamboo(Phyllostachys pubescens Mazel ex H.de Lebaie)and Chinese fir(Cunninghamia lanceolata(Lamb.)Hook.), which are abundant in China, were used as experimental materials in this dissertation. The objectives were firstly to study physical and mechanical properties of Moso bamboo and Chinese fir, composite interface state and glue technology,and then to explore physical and mechanical properties of Moso bamboo/Chinese fir laminated composite made from Moso bamboo strips and Chinese fir wood, and reveal the changing laws of properties on the laminated composite under various forms and conditions. Firstly, the basic physical and mechanical properties on planed Chinese fir wood and Moso bamboo strips without inner and outer layers were conducted to investigate. It had been realized that there were many differences on the physical and mechanical properties between planed bamboo without inner and outer layers and Chinese fir. All those provided basic data and analytical evidence for further studying Moso bamboo/Chinese fir laminated composite. For studying laminated glue property and modification of the composite, The surface wettiability and interior air penetrability of Moso bamboo and Chinese fir were investigated in the dissertation. On the basis of analysis on wettiability principles, the effects of various bamboo surfaces which had been treated by weathered, carbonized and processed in different coarseness respectively were studied by water contact angle changes. The result indicated that water contact angle was increased and wettiability become decrease with the increase of weathered degree and coarseness grade, and that water contact angle was increased slightly with the increase of carbonized degree. Meanwhile the surface weathered degree was evaluated by color characteristics, and chemical components was also analyzed by X-ray photoelectron spectrum analyzer. The result showed that oxygen/carbon ratio was increased along with the increase of weathered degree, and oxidation was also enhanced. In addition, coarseness degree were analyzed and compared between planed and sandedMoso bamboo or Chinese fir surface. Being Compared contact angle changes of various adhesives on different surface of Moso bamboo and Chinese fir with the coefficients of penetrability, it was found that wettiability of polymeric diphenylmethane diisocyanate adhesive (PMDI) was much better than emulsion polymer isocyanate adhesive(EPI), wettiability of phenol-formaldehyde adhesive (PF) and urea-formaldehyde adhesive (UF) were in the middle of above two adhesives. According to penetrability theory for wood, the air penetrability of bamboo and Chinese fir were investigated, including bamboo internode part and its node, carbonized bamboo, Chinese fir sapwood and heartwood. And their penetrating coefficients were also figured out. The result showed that longitudinal penetrability of bamboo was 4－40 times more than that of Chinese fir, and longitudinal penetrability of bamboo internode was also 3 times more than that of bamboo node. It was found that radial penetrability of bamboo was extremely low, and longitudinal penetrability for Chinese fir sapwood was higher than that for heartwood. Basing on the natural trait and surface state of Moso bamboo and Chinese fir, and considering adhesive characteristics and environmental protection, the EPI adhesive, which was higher strength and lower toxicity, was used in gluing bamboo and Chinese fir. They were conducted to investigate that effects of various gluing factors(ratio of spreading adhesive, pressing time and pressure, etc.) and their levels involves in bamboo/Chinese fir glue technology. The notability of important gluing factors was calculated and analyzed by SAS soft ware. It was found that various gluing factors had little effect on modulus of elasticity and rapture, however, pressure and time factors had significant effect on glue line shearing strength. The optimizing glue technology had been obtained through research and experiments. The main parameters...