玻璃纤维/甲基丙烯酸酯基原位固化管道内衬在海水和硫酸中的加速老化行为

Accelerated aging behavior of glass fiber reinforced methacrylate-based cured-in-place-pipe lining in seawater and sulfuric acid

  • 摘要: 原位固化管道(Cured-in-place-pipe, CIPP)内衬用于修复被生物硫酸腐蚀的排水管道,也用于市政排海管道。而玻璃纤维/甲基丙烯酸酯基复合材料用于CIPP内衬,在硫酸和海水环境下的耐久性尚不明确。设计了0.5%硫酸、模拟海水与高温(80℃)加速相耦合的老化实验,以纯水作为对照,基于吸水测试、三点弯曲测试、接触角分析、SEM和FTIR等表征测试方法,研究了玻璃纤维/甲基丙烯酸酯基CIPP内衬的老化行为。结果显示:0.5%硫酸、模拟海水和纯水加速老化1440 h后,弯曲强度分别下降了57.9%、58.4%和57.4%,而弯曲模量没有明显下降;酯键水解生成的羟基部分被氧化为羰基,使树脂老化后颜色发黄;硫酸劣化了树脂表面使润湿性降低,也通过腐蚀表面玻璃纤维促进了水分扩散;海水中盐分析出结晶阻碍了水分扩散,也严重破坏了材料表面的树脂层,也使润湿性增强。提高CIPP内衬的耐久性,重点应该抑制水分扩散劣化界面。可为甲基丙烯酸酯用于CIPP修复材料的耐久性评估提供参考依据。

     

    Abstract: Cured-in-place-pipe (CIPP) lining is used to repair drainage pipes corroded by biological sulfuric acid and is also used in municipal sea drainage pipes. However, the durability of glass fiber reinforced methacrylate-based composite materials used in CIPP lining in sulfuric acid and seawater environments is unclear. This study established two aging conditions: 0.5% sulfuric acid and simulated seawater, with the temperature of 80°C to accelerate aging. Pure water was used as a control. Characterization and testing methods such as water absorption test, three-point bending test, contact angle analysis, SEM, and FTIR were used for the study to evaluate the aging behavior of glass fiber reinforced methacrylate-based CIPP lining. The results show that the bending strength decreases by 57.9%, 58.4%, and 57.4% respectively, after accelerated aging in 0.5% sulfuric acid, simulated seawater, and pure water for 1440 hours. While the bending modulus does not show a significant decrease. The hydroxyl group generated by the hydrolysis of the ester bond is partially oxidized to a carbonyl group, causing the resin to turn yellow after aging. Sulfuric acid deteriorates the resin surface and reduces the wettability, and also promotes water diffusion by corroding the surface glass fiber. The crystallization of salt in seawater hinders the diffusion of water and severely damages the resin layer on the material surface, leading to enhanced wettability. To enhance CIPP lining durability, efforts should focus on inhibiting moisture diffusion and degradation at the interface. This study can provide a reference basis for the durability evaluation of methacrylate used in CIPP repair materials.

     

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