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用红外吸收光谱分析法、动态力学性质测试法和热分析法研究了国产顺丁生胶的热氧化和光氧化。发现在光或热的作用下都会出现顺式—1·4结构转变为反式—1·4结构的异构化现象。检测到伴随断链效应生成的种类繁多的含羟基或羰基的氧化产物,而光、热氧化两种过程中所生成的氧化物的种类一样,但浓度分布不同。顺丁胶热氧化初期断链效应占优势,后期交联效应占主导,因此,它的动态切变模量先下降后陡升。醚式氧桥是其交联键的一种形式,它使顺丁胶的热稳定性下降。以相对切变模量、羟基指数和羰基指数为指标,鉴定了18种稳定剂在顺丁胶中的抗光、热氧化的效能。
The thermal oxidation and photooxidation of domestic polybutadiene rubber were studied by infrared absorption spectroscopy, dynamic mechanical property test and thermal analysis. It was found that under the action of light or heat, the isomerization phenomenon of the cis-1.4 structure to the trans-1.4 structure occurred. A wide range of oxidation products with hydroxyl or carbonyl groups were detected with the chain scission effect. However, the types of oxides formed during both photooxidation and thermal oxidation were the same but with different concentration distributions. The initial chain scission effect of butadiene rubber thermal oxidation predominates, and the post-crosslinking effect is dominant. Therefore, its dynamic shear modulus first drops and then rises sharply. Ether ether oxygen bridge is a form of its cross-linking, which decreases the thermal stability of butadiene rubber. Based on relative shear modulus, hydroxyl index and carbonyl index, 18 stabilizers were identified as light and thermal oxidants in butadiene rubber.