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Characterization of ultrahigh molar mass, water‐soluble, cationic polyelectrolytes
Author(s) -
Kulicke W.M.,
Jacobs A.
Publication year - 1992
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19920610106
Subject(s) - molar mass , polyelectrolyte , radius of gyration , chemistry , cationic polymerization , light scattering , static light scattering , virial coefficient , methacrylate , polymer chemistry , scattering , analytical chemistry (journal) , chemical engineering , polymer , organic chemistry , copolymer , thermodynamics , optics , physics , engineering
Four different cationic polyelectrolytes were investigated, which are used as flocculating agents in the dewatering of sediments from Hamburg harbour. The chemical structures of these polyelectrolytes were characterized by means of IR and 13 C NMR spectroscopy. The substances concerned are the two copolymers of acrylamide formed with acrylate and methacrylate esters, and the homopolymers of these esters. The charge density was determined with the aid of titrimetric methods and quantitative evaluation of IGATED 13 C NMR spectra. Determination of the molar mass and steric characterization were carried out by multi‐angle laser light scattering. In order to resolve the experimental problems which arise especially during light scattering in water‐soluble cationic systems, a special method of sample preparation has been devised to remove impurities, which will be described in detail. This method involves the combination of filtration and ultracentrifugation. Evaluation of the light scattering data provided the values for the molar mass M w′ the second virial coefficient A 2 and the radius of gyration 0,5 Z , which also gives information about the solution structure. By comparing the curve of the scattering function extrapolated to zero concentration with model curves and with the aid of the a exponent of the [η]‐M‐relationship, it can be seen that the polyelectrolyte has a highly expanded coil structure in salt solution. This can be primarily attributed to the steric influence of the side groups.