天然橡胶在约束条件下的剪切疲劳机理研究

研究了两种不同炭黑含量的天然橡胶硫化胶在约束条件下的剪切疲劳过程,并采用红外光谱、凝胶色谱、气相色谱-质谱联用和热重分析等方法分析了两种不同疲劳的产物。结果表明,低炭黑含量的天然橡胶硫化胶在剪切疲劳过程中会有黑色粘稠油状产物出现在裂口边缘,这是硫化胶降解和氧老化产物以及部分残留配合剂的混合物;高炭黑含量的天然橡胶硫化胶在剪切疲劳过程中会有黑色粉末团聚状固体产物出现在裂纹外侧,这是疲劳降解与磨耗共同作用下的混合物。分析表明,约束条件下的天然橡胶硫化胶剪切疲劳表现出老化疲劳模式和磨耗疲劳模式。

Shear Fatigue Mechanism of NR Vulcanizate under Constrained Condition

The shear fatigue process of two kinds of different carbon content of NR vulcanizate under constrained condition was investigated. Moreover, two different fatigue products were investiga- ted by IR, gel permeation chromatography （GPC）, gas chromatography-mass spectrometry （GC-MS） and thermogravimetry （TG）. The results showed that a black viscous oil-like product produced by the low-carbon content specimen appeared in the crack edge during the process, which was mixture of degradation and oxidizing aging products as well as residual additives. A black crumbing produced by the high-carbon content specimen appeared outside of the crack, which was the product from combined action of degradation and abrasion. Analysis showed that two different models were present in process of shear fatigue under constrained condition for NR vulcanizate, which was aging fatigue and abrasion fatigue.