【作者】 魏晓丽；

【导师】 赵家森； 孙玉山；

【作者基本信息】 天津工业大学 ， 材料学， 2004， 硕士

【摘要】 本研究采用加速老化实验方法(烘箱法)，对聚丙烯纤维分别在120℃、125℃、130℃和135℃条件下进行了热老化实验，绘制了老化曲线，在此基础上建立了预测聚丙烯纤维老化耐用期的数学模型；估算了聚丙烯土工布在正常使用温度下的老化耐用期；讨论了临界值的选取对方程及估算结果的影响；对经不同处理的纤维试样进行了热老化对比实验，及加压和不加压土工布的热老化对比实验，并从机理上分析了几个主要的外界因素(水、酸、碱、金属离子、压力等)对其寿命的影响程度。从而可为聚丙烯土工布的开发和应用提供一定的参考依据。 实验所建立的预测聚丙烯纤维的耐用期的方程为： logK=5.55×10~3(1/T_o-1/T_r) 对比实验结果表明：酸(pH=5)、碱(pH=9)、纯水和水中的金属离子都会影响聚丙烯纤维的耐老化性能。其中，酸、碱的作用导致纤维耐用期降低约13％，水的作用导致纤维耐用期降低约20％，在铜离子的作用下，纤维的耐用期约下降了54％。可见，金属离子对聚丙烯土工布纤维的寿命影响最大，水的影响次之，酸、碱对其影响最小；在受压情况下，土工布的寿命明显降低。 一般较常见的关于土工布老化的影响因素的研究，多以光、水分、酸碱为主。本研究发现：即使是微量的金属离子就会对聚丙烯土工布的老化产生很大影响，使其寿命大大降低。而且，当今环境污染比较严重，土壤里可能存在着大量的重金属离子。对于常用于地下埋置使用的土工布，金属离子对其寿命的影响是应该重点考虑的一个因素。 临界值C的选择，对方程log τ=a/T+b中的系数a影响并不是很大，但在150℃的条件下，所测得的参比耐用期是不同的，造成了预测结果的很大的差别。因此，在实验中选取合适的临界值相当重要。本研究认为：选取初始值的1/3作为老化的终点，是比较可靠和符合实际的。更多还原

【Abstract】 Aging of geotextile attracted a great deal of attention in recent years, because it is very important to the stability of the whole work, and geotextile are used widely as reforcing medium in structures. Especially, the prediction of geotextile’s aging-time has become one of the focuses nowadays. However, most of the studies are on plastics, and few are on fibers.In this paper, systematic investigations on the aging-time of polypropylene fibers at different temperatures have been made. This research has laid particular emphasis on how to build up the equation of geotextile’s aging-time, which was based on Arrhenius equation (K=A e-E/RT). By means of oven accelerated aging test, the experiments were carried out at 120℃, 125℃, 130℃ and 135℃, respectively. Then the lifetime of the fibers at normal temperature could be calculated according tothe equation. where τ f is the final durability period; K is compositive multiplication coefficient; τ r is reference durability period; τr is reference temperature, 150℃; τi is using temperature (K); Kj is multiplication coefficient at τi; Fi is time fraction of ℃i, Fi=1.Moreover, the effects of changing critical value on the equation were elucidated. Furthermore, the effect of soil’s acidity (pH=5) and basicity (pH=9), pure water and copper ion in the water on the aging-time was discussed.The results showed that acid and alkali made the fiber’s lifetime decrease about 13% and water make the fiber’s lifetime decrease about 20%, while copper ion shorten the aging-time of the fiber more than 54%. Acid, alkali, metal ion wouldshorten the lifetime of PP fiber, and the effect of metal ion is the biggest, the effect of water is the second, acid and alkali is the smallest. Under the pressure the aging rate of PP geotextile would be accelerated.This study also indicated that fiber grade anti-aging PP chip could be spun at conventional temperature; plastic and flat fiber grade would be spun at high temperature. However, high spun temperature would make the antiager consume and decompose, which will shorten the geotextile’s lifetime. Therefore, the antiager and the spinnability of resin were very important.As there are different effect factors in different environment, experiment should be done based on particular natural conditions.更多还原