Study On The Influence Of Mixing Process Parameters On The Properties Of NR/BR Blends

The side rubber of a tire is mainly composed of natural rubber and butadiene rubber(NR/BR)blends.In practical uses,tire side will deform and age due to various factors including pressure and temperature.Therefore the properties of side rubber must satisfy special requirements.In the mixing process,the technological conditions are very important to the properties of mixing rubber products.Based on the above background,five mixing process parameters are chosen to investigate the influence on the properties of natural rubber/butadiene rubber blend.The chosen mixing process parameters include the combination ratio of NR/BR,the feed sequences of rubber compound and carbon black,the mixing time of carbon black,the rotor speed of internal mixer,and the temperature of cooling water.The properties of rubber are characterized by Mooney viscosity test,rheological properties test,mechanical properties test,crack growth test,flex cracking test and dynamic mechanical analysis.Based on the study of the performance of rubber with different ratio of NR / BR,the characteristics of NR and BR and the influence of the change of blending ratio on the properties of rubber are discussed,then the optimum blending ratio are obtained.The relationship between feeding sequence and rubber properties is studied.Through the comparison of rubber properties,the difference of carbon black dispersion in rubber under different feeding sequence and the difference of reinforcing effect of carbon black on NR and BR are concluded.The most suitable feeding sequence is determined.The influence of mixing time of carbon black on rubber properties is studied.The change trend of rubber properties with the increase of mixing time is summarized.The rule of influence of mixing time on dispersion of carbon black and molecular weight of rubber is deduced,and the best mixing time is obtain ed.Based on the study of the influence of rotor speed on rubber properties,the changing trend of rubber properties with the increase of rotor speed is summarized.The rules of rotor speed affecting mixing temperature,dispersion of carbon black and molecular weight of rubber are obtained,and the best rotor speed is determined.The differences of rubber properties under different cooling water temperatures are compared.The effects of cooling water temperature on mixing temperature,dispersion of carbon black and molecular weight of rubber are summarized,and the best cooling water temperature was determined.