AbstractThe use of ultrafiltration in determining microgel contents of synthetic rubbers containing high levels of microgel was extensively studied. From experiments with a nonagitated filtration cell, it was found that accurate microgel contents could be obtained only when concentration polarization of the membrane was disallowed. GPC studies of the filtrates indicated that changes in the molecular weight distribution of the filtered polymer occured as a result of the occurrence of concentration polarization. The use of an agitated filtration cell was found to inhibit the occurrence of concentration polarization, allowing the proper filtration of larger volumes and higher concentrations of solutions of these types of polymers.
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