应变速率对炭黑填充丁苯硫化胶应力-应变行为的影响

Influence of Strain Rate on Stress-Strain Behavior of Carbon Black Filled Styrene Butadiene Rubber Vulcanizate

橡胶材料的应力-应变行为是决定其应用性能的关键指标之一,不同使用条件特别是应变速率对橡胶材料的性能提出了不同的要求。从炭黑补强橡胶的角度出发,系统研究N330、N660和N774这3种炭黑填充丁苯硫化胶的应力-应变行为随应变速率的变化情况。实验发现,丁苯硫化胶的定伸应力均随应变速率增加而增加,且炭黑的补强性能越高定伸应力的增加幅度越大;对任一硫化胶,定伸应力的增长幅度均随应变的增加而减小;当应变达到某一临界值(如300%)时,应变速率对定伸应力增长幅度的影响趋于一致,与是否填充炭黑及炭黑的补强性能无关。在准静态的拉伸测试中,炭黑在橡胶基体中形成的网络化结构将随应变的增加而逐渐破坏,但破坏程度主要与应变大小有关而与应变速率无关。

The stress-strain behavior of rubber compounds is one of the key items to determine its application performance,and the different service conditions,especially the strain rate,have variable requirements for the performance of rubber compounds.The influence of tension strain rate on the stress-strain behavior of styrene butadiene rubber(SBR)vulcanizates filled with 3 kinds of carbon black was investigated from the point of view of rubber reinforcement.It was found that the stress at a given elongation of any SBR vulcanizate increases with increasing strain rate,and the more reinforcing the carbon black,the higher increment rate the stresses.For any given SBR vulcanizate,the stress increment rate decreases with the increase in strain.As the strain exceeds the critical points,such as 300%,the effect of strain rate on the rate of stress increase is becoming equivalent and independent of carbon black grades.From a filler reinforcement point of view,the tensile modulus of filled vulcanizates in the plateau region is governed by the surface activity of the carbon black.In quasi-static tension test,the networking of carbon black in vulcanizate will be gradually broken with increasing strain,which the break-up is predominantly controlled by strain rather than strain rate.