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New ASTM tests to measure carbon black, silica dispersion

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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 and precipitated hydrated silica with differing ratios of organosilanes. This affects downstream factory performance in extruding, calendering, molding and cured physical properties.

Two years ago a new standard method for measuring the Payne Effect was developed as ASTM D8059 using the Premier-brand RPA. Also in 2011, a new standard method was developed using a reflected light microscope to measure state of mix under ASTM D7723.

In this study, the Premier RPA Rubber Process Analyzer 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 Alpha Technologies Premier RPA.