气相法白炭黑填充天然橡胶的裂纹扩展机理

Crack Growth Mechanism of Fumed Silica Filled Natural Rubber

研究了不同粒径,不同份数的白炭黑对天然橡胶(NR)裂纹生长行为的影响。采用具有裂纹生长测试功能的DMA(DMA-Crack Growth)对预割口试样的裂纹扩展速度进行测试。利用超高速显微摄像技术对裂纹扩展尖端进行在线追踪,得到裂纹扩展尖端的动态显微图像。结果表明,添加20 phr原生粒径为15 nm的气相法白炭黑时,裂纹尖端韧带均匀且细密,对裂纹生长起到很好的阻碍作用;添加20 phr原生粒径为7 nm的气相法白炭黑时,对试样的裂纹生长有不利影响。

The rubber crack growth behaviors of natural rubber（ NR） influenced by silica particles with different sizes and contents were studied. A special dynamic mechanical analyzer（ DMA） of crack growth test function was used to measure the crack growth rates. The crack tip was photographed by an ultra-high speed camera. The results show that the ligaments at the crack tip are uniformly and closely distributed,when 20 phr silica with the primary particle size of15 nm is embedded in the NR matrix,the crack growth behavior is hindered obviously. However,when adding 20 phr silica with the primary particle size of 7 nm,crack growth rate is adversely affected.