氢化丁腈橡胶在高温盐酸中的老化过程

Degradation of Hydrogenated Nitrile-Butadiene Rubber in Hydrochloride Aqueous Solution at High Temperature

研究了氢化丁腈橡胶(HNBR)在不同温度下和10%的盐酸中,老化前后的化学组成、微观结构和力学性能变化。通过固态碳核磁、X射线光电子能谱、扫描电镜、红外光谱和拉伸测试表征分析了经盐酸浸泡和未经浸泡的HNBR试样。由这些结果可知,在110℃和130℃的条件下,HNBR发生的老化反应主要是腈基水解为酰胺基,并有少量羧酸基产生。当温度升高到150℃时,会有一部分碳酰胺基转变为羧酸基,并且伴有少量氨气生成。在170℃时,随着温度的进一步升高,氨气的产生速度加快;生成大量的羧酸基团和氨气,导致HNBR基体内部形成大量孔洞;与此同时,碳酰胺基团之间会发生缩合反应,产生交联,导致HNBR的硬度提高。这些反应很好地解释了氢化丁腈橡胶材料老化前后的力学性能变化。

The degradation of hydrogenated nitrile-butadiene rubber （HNBR） in 10% hydrochloride aqueous solution at different high temperature was investigated. The samples unexposed and exposed to hydrochloride aqueous solution were characterized by 13C-nuclear magnetic resonance, X-ray photoelectron spectroscopy, infrared spectra, scanning electron microscopy and tensile test. From these characterizations, it can be concluded that the hydrolysis of cyanic group to carbonyl amide carboxyl acid is dominant reaction comparing to the conversion to carboxyl acid at 110 and 130 ℃. At 150 ℃, some carbonyl amide groups are altered to carboxyl acid groups and a little hit of ammonia gas produce. However, at 170 ℃, a great deal of carboxyl acid groups and ammonia gas produce lead to forming voids in HNBR matrix and condensation reactions occur between carbonyl amide groups leading to hardness increase of the HNBR matrix. The variety of mechanical properties can be well explained by these reactions.