Compounds based on different base elastomers will break down in different ways during the mixing process and have different degrees of interaction with carbon black, which affects carbon black dispersion. This affects downstream factory performance in extruding, calendering and molding.
Last year a new standard method for measuring the Payne Effect was developed as ASTM D8059 using the RPA. Also, in 2011 a standard method was developed using a special reflected light microscope to measure state of mix by percent carbon black dispersion under ASTM D7723.
In this study, an RPA 2000-brand Rubber Process Analyzer with EDR was used to measure the differences in rheological behavior from using different base elastomers with variation in the applied work history during mixing. Model rubber compounds were prepared and tested using several different base elastomers. Processability characteristics as seen in the Payne Effect were measured for these mixed stocks with varying work histories using the RPA 2000 with EDR. Comparisons also were made with the AlphaView Dispergrader-brand reflected light microscope.