Method for measuring non-porous surface area of carbon black

Claim 1

A method of measuring the non-porous surface area of a porous carbon black comprising, adding an exact predetermined volume of cetyltrimethylammonium bromide solution to a weighed sample of the carbon black, dispersing the sample in the solution to cause part of the cetyltrimethylammonium bromide to be adsorbed onto the carbon black, flowing a reference solution of cetyltrimethylammonium bromide through a measuring loop to measure a predetermined volume of the reference solution, passing the predetermined volume of reference solution directly from the measuring loop into a high pressure liquid chromatography column to separate the cetyltrimethylammonium bromide from the solution, directly measuring the cetyltrimethylammonium bromide from the solution by generating a chromatographic reference peak, flowing the carbon black sample dispersion out of the container and directly through a filter-containing cartridge for a predetermined length of time, producing a non-carbon black containing filtrate, passing the filtrate directly from the filter through a measuring loop to measure a predetermined volume of the filtrate, passing the predetermined volume of the filtrate directly from the measuring loop into a high pressure liquid chromatography column to separate the cetyltrimethylammonium bromide from the remainder of the filtrate, directly measuring the cetyltrimethylammonium bromide from the filtrate by generating a chromatographic filtrate peak, and determining the non-porous surface area of the carbon black according to the following formula, ##EQU2## where K' and K" are calibration constants, R is the ratio of chromatographic filtrate peak area to chromatographic reference peak area, W is the weight of the carbon black sample, and M is the percent moisture in the carbon black sample.

Claim 2

A method of measuring the non-porous surface area of a porous carbon black comprising, adding an exact predetermined volume of cetyltrimethylammonium bromide solution to a weighed sample of the carbon black, dispersing the sample in the solution to cause part of the cetyltrimethylammonium bromide to be adsorbed onto the carbon black, flowing a reference solution of cetyltrimethylammonium bromide through a measuring loop to measure a predetermined volume of the reference solution, passing the predetermined volume of reference solution directly from the measuring loop into a high pressure liquid chromatography column to separate the cetyltrimethylammonium bromide from the solution, directly measuring the cetyltrimethylammonium bromide from the solution by generating a chromatographic reference peak, flowing the carbon black sample dispersion out of the container and directly through a filter-containing cartridge for a predetermined length of time, producing a non-carbon black containing filtrate, passing the filtrate directly from the filter through a measuring loop to measure a predetermined volume of the filtrate, passing the predetermined volume of the filtrate directly from the measuring loop into a high pressure liquid chromatography column to separate the cetyltrimethylammonium bromide from the remainder of the filtrate, directly measuring the cetyltrimethylammonium bromide from the filtrate by generating a chromatographic filtrate peak, and determining the non-porous surface area of the carbon black according to the following formula, ##EQU2## where K' and K" are calibration constants, R is the ratio of chromatographic filtrate peak area to chromatographic reference peak area, W is the weight of the carbon black sample, and M is the percent moisture in the carbon black sample.