Study On Segregation Behavior Of Silica In NR Combined System

In the field of rubber processing,segregation behavior refers to the uneven distribution of nano-filler(such as silica and carbon black)in blends.The segregation behavior of silica in NR/SBR and NR/NBR was investigated by means of Fourier transform infrared spectrum and dynamic mechanical analysis.It was detected quantitatively.Firstly,for NR/SBR filled with 40 phr silica,the effects of blending ratio and component-added order on the segregation behavior of silica were studied.The results showed that the silica was easy to locate at NR phase for the blends that we mixed NR with SBR and then added to silica.It was independent on the ratio between NR and SBR.With the increase of the content of NR,the Payne effect and Mullins effect of the system gradually were weakened,the degree of filler network gradually were decreased.For blends with different component-added order,silica was always easy to locate at the rubber phase that was mixed with silica firstly.The results showed that the vulcanization that we mixed NR with silica and then added to SBR had the lowest degree of network,the Mullins effect and Payne effect was the lowest.The reason was that silica was always easy to locate at NR,and silica at NR has good dispersion and low degree of network.And the vulcanization that we mixed NR with SBR and then added to silica had the highest degree of network,the Mullins effect and Payne effect was the strongest.This reason was that silica was mainly distributed at the phase interface near the side of the NR phase and the NR phase is wrapped.And for NR/NBR blends filled with 40 phr silica,segregation behavior of silica was investigated.For compounds and vulcanizates of NR/NBR,silica was easy to locate at rubber phase that the content was less.With the increase of the content of NR,the Payne effect and Mullins effect of the system gradually were weakened,the degree of filler network gradually was decreased.Comparing with the segregation behavior of NR/SBR and NR/NBR systems,it was found that the polarity of the rubber had a great influence on the segregation behavior of silica.The segregation behavior of NR/SBR has nothing to do with the blending ratio,while the NR/NBR is easy to locate at rubber phase that the content was less.Compared with the segregation behavior of compounds and vulcanizates at NR/SBR and NR/NBR blends,it can be seen that segregation behavior of vulcanizates in these blends was decreased.The reason was the high temperature during the vulcanization process and the redistribution of silica in the system.