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Preparations and Characterizations of Wood-polyurethane Composites with Fast-grown Poplar

Author: WuZuo
Tutor: GaoZhenHua；GuJiYou
School: Northeast Forestry University
Course: Biological materials engineering
Keywords: Poplar Polyurethane Prepolymer Wood composites Catalyst Flame retardant
CLC: TB332
Type: Master's thesis
Year: 2010
Downloads: 121
Quote: 0
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Abstract


Since the national implementation of natural forest protection project, vigorously plantations has become an important way to solve our timber supply and demand, however artificial fast-growing the forest wood material is soft, low-density, poor processing performance characteristics limit their use, so the current often modified by wood processing or preparation of wood composite materials to improve the performance of plantation timber materials. Based on preliminary exploration, the selection of the papers fast-growing poplar solid wood and veneer as the main raw material, foam polyurethane resin pre-polymers modified resin using scanning electron microscopy (SEM), cone calorimeter (CONE) and the routine analysis of composite materials characterized treated wood and poplar / the polyurethane composites drugs weight gain, dimensional stability, mechanical strength, and combustion performance, and other performance indicators, evaluation dipping time, dipping method, dipping sequence, curing, catalyst type and other parameters for the fast-growing Yang solid wood / polyurethane composites; adjust the resin concentration at the same time, compression ratio, dry home time, flame retardant types of parameters further prepared composites with better quality. Results showed that: different NCO / OH molar ratio, the impregnation sequence, the immersion time, the curing method of the resin in the wood impregnation depth, different forms of foam, directly affect the performance of the treated wood was found by SEM. The experimental optimization draw: the synthetic formulations NCO / OH 3.0 polyurethane prepolymer as a resin-impregnated, the concentration is 15%; process uses twice the negative pressure, respectively, the catalyst and a polyurethane resin impregnated; ordinary heating to achieve curing. Catalyst impact on the performance of solid wood / polyurethane composite catalyst diethylenetriamine most significantly improve the mechanical properties and dimensional stability of the material; role of catalyst N-methyl morpholine can effectively improve the dimensional stability of the material , but the mechanical properties to improve the general; introduced into the catalyst after the flame resistance of the composite material are improved. / Polyurethane composites optimum process for the preparation of poplar veneer: polyurethane resin concentration of 30%; synthetic resin of NCO / OH molar ratio of 6.0; compression rate of 20% in the composite material; dry set time was 2h. NH4H2PO4 AICl3 · 6H2O timber retardant treated poplar veneer can then be made into composite resin weight gain, bending strength decreased slightly hygroscopic increase, but the volume expansion rate of the composite and little effect, good flame retardant properties of the composite material, the elastic modulus and the char yield is significantly improved and the increase in flame retardant anti-bleed.

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