Abstract: Fiber reinforced plastic (FRP) exhaust inner tube is widely used in new coal-fired power plants. In this paper, according to the actual temperature condition design experiment of coal-fired power plant,the changes of appearance, quality, rubber content and mechanical properties of FRP exhaust inner tube in 90 ℃, 135 ℃, 180 ℃ under high temperature conditions were studied in this paper. By comparing the mechanical properties of vinyl ester resin under different temperature conditions and scanning electron microscope (SEM), the analysis results of the cross section of the FRP smoke inner barrel were studied, the change tendency and reason of mechanical properties of FRP smoke inner tube at elevated temperature are discussed emphatically. The results show that the color of the FRP exhaust inner tube is deepened with the increasing of temperature, and the sample is almost carbonized and black at 180 ℃, and the change of mass and rubber content is caused by the quality change of the resin matrix. The result is that the quality and the glue content decrease with the increase of the cycle length and the temperature, and the mechanical properties are similar with vinyl ester resin, and the trend of the increase in the first time is decreased. The mechanical properties of 60 d are best under 135 ℃, which is around the glass transition temperature (T_g). At a temperature of 180 ℃, which is much higher than that of the glass transition temperature, the mechanical properties of the material decreased significantly at the later stage, but it remained about 80% of the strength retention rate.

Key words: fiber reinforced plastic (FRP) exhaust inner tube, vinyl ester resin, high temperature, performance