Anthony R. Cooper

Purification of polymeric dyes by ultrafiltration

Ultrafiltration is a widely accepted technique for the purification of polymeric or colloidal materials. We have previously reported1 on the purification of a water soluble polymeric dye which contained water soluble organic impurities. The preparation of another class of polymeric dyes has been described2 which are water soluble but the organic impurities are water-insoluble. The organic impurities are capable of bonding hydrophobically to the polymeric dye in aqueous solution, which causes special problems in their purification3 and analysis4. The requirement for high purity arises from their intended use as food additives5,6. This work describes the development of a purification method for these polymeric dyes by ultrafiltration in mixed aqueous solvents.

Improved ultrafiltration processes by partial recycle of ultrafiltrate

Abstract The economics of ultrafiltration processes may be improved in certain situations by partially recycling the ultrafiltrate. These situations include purification processes involving the use of additives in the makeup stream or processes where a recoverable product is present in the ultrafiltrate. A mathematical solution to this approach has been obtained to calculate the number of stages required as a function of the purification desired, the rejection coefficient of the species being removed, and the number of diavolumes. Some economic comparisons have been performed for multiple-stage ultrafiltration processes and compared with conventional single-stage diafiltration processes.

Characterization and Properties of Macromolecules. XII. Numerical Treatment of Gel Permeation Chromatography Data

Abstract Gel permeation chromatography provides a continuous recording of polymer concentration as a function of elution time. The latter may be converted by appropriate calibration into molecular weight. The chromatogram may be analyzed numerically to yield the various molecular weight averages. This process involves a number of assumptions and approximations. The magnitude of the errors introduced in the calculated molecular weight averages by the methods described in the literature are reported.

Demetallation of Chelating Polymers by Diafiltration in the Presence of a Permeable Complexing Agent

Polymeric chelating solutes are retained by ultrafiltration membranes of appropriate porosity. The factors influencing the transport of a metallic impurity by diafiltration in the presence of a permeable complexing agent have been determined. This process may find applications where difficulties are encountered with conventional metal removal processes.