The Study Of Hygrothemal Aging Of Bamboo/wood Composite Electrothermal Plywood

Using electric heating floor to heat is a new type of heating mode,which has advantages of fast heating speed, comfort feeling and less space.Bamboo/wood composite electrothermal plywood is a good materia to produce the electric heating floor. This kind of floor not only has excellent heating function, but also has very good interior decoration effect. But electric heating paper layer will produce adverse effect to bond intensity, and it will occur wet and heat aging when the floor is at the condition of high temperature and high humidity for a long time. Therefore, researching the impact of wet and heat aging on the material and evaluating and predicting it have great significance for both scientific research and actual production.This normal electricity aging test and different kinds of artificial accelerated aging test for bamboo/wood composite electrothermal plywood, and then tests related performance indicators to analyze the correlation of normal electricity aging and artificial accelerated aging, optimizes the accelerated aging test method, explores the varation of related index.Through analyzing the test results, we can get the following conclusion:(1)The adhesive type, hot-pressing time, electric papertype, bamboo veneer layers and their interactions have an important influence on the bond strength and heat-resist ant dimension stability. When the adhesive used modified melamine resin adhesive, hot pressing time was 2.0 min/mm, electrothermal paper was choosed NL-110, bamboo ven eer layer was 2 levels,the combination was the best, and the bond strength, length of heat shrinkage, width of heat shrinkage were more than variance test group increased by 48%,-16%,-8%.(2)The greater current, higher temperature and higher environmental humidity lead to faster reduction of bond strength carbon fiber electric heating paper layer. When the materils happen overload current aging, alternating temperature and humidity aging, constant temperature and humidity aging, they get similar bond strength change trend to normal electricity aging, and the aging speed becomes quickly. In this four kinds of aging way, the impregnated stripping rate of carbon fiber electric heating paper layer is 0, the bamboo/wood composite electrothermal plywood has good dipping stripping resistance performance.(3)The materials have the similar change trend of damp and heat dimension stability under thenormal electricity aging and overload current aging conditions. Overload current aging is suitable for researching the damp and heat dimensional stability of bamboo/wood composite electrothermal plywood.(4)The glossiness reduction speed of overload current aging is twice as big as the normal electricity aging. For the glossiness, the overload current aging is suitable for as a normal electricity aging prediction mode. In normal electricity aging, lightness decreases evenly along with aging time, while color difference increases evenly. In the 4kinds of artificial accelerated aging way, L* reduce speed is fast,then becomes slowly, as far as the growth speed of ΔE.(5)FTIR showed that with the aging of conduct of the trial,-OH and C=O was reductionde, cellulose, hemicellulose, lignin decomposition, hydrophilic became lower, contact angle increased, free energy reduced, and leaded to color changing.(6)As the extension of power-on time, the resistance decreases firstly and then becomes stable. The electrical performance of carbon fiber electric heating paperis stable. In overload current aging and normal electricity aging test, the change rule of resistance is similar, so the overload current aging test can be use to predict theresistance change law of normal electricity aging.