| Rubber materials are widely used in the fields of automobile,architecture,ship and aerospace.With the implementation of the national strategy towards dark blue,the marine climate environment puts forward higher requirements for the performance of rubber materials.Nitrile rubber is widely used in marine and offshore applications because of its excellent mechanical properties and medium resistance.The mechanical properties of NBR materials change significantly in marine climate.Therefore,this subject takes nitrile rubber material as the research object,simulates its aging behavior under high salt fog,high temperature,high humidity,strong ultraviolet and other simulated marine climate environment by accelerated aging test,reveals its aging mechanism under multi factor coupling conditions,and provides basis for the preparation and service life evaluation of high-performance rubber composite structure,which has important theoretical significance and application value.Firstly,the accelerated aging test method of NBR materials in marine climate environment was established.Based on the review of marine climate environment at home and abroad,the aging test conditions of simulated marine climate environment such as salt spray,damp heat and UV are determined,and the corresponding aging test scheme was put forward.Based on this,the aging test of nitrile rubber materials with single factor and multi factor coupling was carried out.Secondly,the aging behavior of NBR in marine climate was studied.Based on the aging test,the changes of quality,hardness,compression set and tensile mechanical properties of NBR materials under different aging time,salt spray,damp heat and UV damp heat were studied.The results show that the quality of salt spray aging and UV damp heat coupling aging didn’t change obviously on the whole,and the change of damp heat aging was more obvious.The compression set rate shows an increasing trend.The environmental factors affecting the compression set rate of rubber specimens at the initial stage of aging were UV damp heat aging,damp heat aging and salt spray aging in order.Hygrothermal environment and ultraviolet hygrothermal environment have great influence on the tensile behavior of NBR;With the increase of aging time,the strain of NBR material at the same stress decreases,and the effect of salt spray aging is small.Finally,the aging mechanism of NBR under marine climate was revealed.By means of infrared spectrum analysis,the aging and Degradation Laws of nitrile rubber materials in simulated marine climate such as salt spray,damp heat and UV were systematically analyzed,the evolution mechanism of functional groups of rubber polymer materials was revealed,and the influence mechanism of mechanical properties was further explained,which provided support for the long-life service of rubber materials in marine climate.The results show that oxygen-containing additives such as carboxyl(-COOH)or hydroxyl(-OH)are easy to migrate during aging,and water and chloride ions may penetrate into the samples;Damp heat aging is mainly reflected in the change of peak intensity;However,the peak value at C=O decreased after 16 days of UV hygrothermal aging,and the reaction may have occurred or the related oxidants may escape with the deepening of aging;The increase of methyl group and the decrease of methylene group indicate that the chain may be broken. |
