Preparation and characterization of membranes with positively charged main chain from polyethylenimine

Abstract

SYNOPSISA membrane, which has positively charged groups in the polymer main chain, was prepared from polyethylenimine by crosslinking and successive alkylation. Dibromoalkane was used as a crosslinking agent. The crosslinked membrane was alkylated using methyl iodide under several conditions. Elemental and ICP emission analyses were introduced to measure the rates of alkylation and quaternization. From the membrane potential measurement, the effective charge density was estimated. The highest value was about 1.0 M, which was obtained by a prolonged alkylation time. This value was larger than that of some commercial ion exchange membranes. The effective charge density, which was obtained by the last alkylation procedure, was 10 times larger than that of the former one, though the rate of quaternizing increased by less than a factor of two. This implies that the activity constant in the membrane increased when the charge density is increased.

Spectroscopic study of the modification of cellulose with polyethylenimines

“…In acidic or neutral pH conditions the amine groups are partially protonated and PEIs behave as cationic polyelectrolytes that can be easily bonded to negatively charged surfaces. Because of this cationic character, polyethylenimines have been extensively used in the last decades for controlling colloidal stability and surface properties in many application fields 1–8. Polyethylenimines can be found in the manufacturing of coatings, adhesives, food packaging films, textile fibers, and medical devices.…”

Novel, positively charged membrane from a blending, crosslinking, and coagulation procedure

“…Charged membranes have found applications in many fields, including the separation of protein mixtures, the separation of macromolecules with similar molecular weights but different charging properties,1 salt production,2 and the concentration of electrocoating paint rinsing water 3. In addition, charged membranes are also very important for physical and chemical studies of model systems 4…”