Influence of Processing Techniques on Carbon Black Dispersion and Mechanical Performance of Polyisoprene-based Rubbers
The main components of natural rubber,polyisoprene rubber,and bionic rubber are all cis-1,4-polyiso-prene,but there are certain differences in components such as proteins and phospholipids.These differences in com-position may lead to different responses of rubber to compounding processes,resulting in variations in the dispersion of fillers in rubber and subsequently affecting the dynamic and static properties of vulcanized rubber.In order to investigate the variation patterns of filler dispersion and rubber mechanical properties of polyisoprene rubbers under different mixing processes,this study employed N220 carbon black as a filler and systematically investigated the carbon black dispersion and dynamic/static properties of natural rubber,polyisoprene rubber,and bionic rubber under four processing techniques.The results of the study show that the filler dispersion and mechanical properties of natural rubber and polyisoprene rubber exhibited a stronger response to the carbon black incorporating time,while bionic rubber showed a weaker response.With increasing carbon black incorporating time,the mean agglomerate size of natural rubber and polyisoprene rubber decreased from approximate 22 μm and approximate 19 μm to approximate 9 μm,resulting in a significant improvement in dynamic/static properties.In contrast,under the same processing conditions,the mean agglomerate size of bionic rubber decreased from approximate 20 μm to approximate 16 μm,and the carbon black dispersion state was poorer.On the other hand,bionic rubber showed a more sensitive response to plasticization time,and an extended plasticization time significantly reduced the mean agglomerate size of carbon black,enhancing its tensile fatigue performance.Accordingly,this study designed a process combining a longer plasticization time(6 min)with compounding,further enhancing the tensile fatigue performance of bionic rubber.To elucidate the reasons for the differential response of bionic rubber to compounding and plasticization processes,the study explored the variation patterns of Mooney viscosity and molecular weight of bionic rubber under different processing conditions.It was found that moderate molecular weight and a relatively narrow molecular weight distribu-tion were conducive to improving the tensile fatigue performance of the rubber.
Polyisoprene-based rubberDispersion of carbon blackProcessing responseMechanical property
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