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Potentiometric Behavior of Polyampholytes Based on N , N ′‐diallyl‐ N , N ′‐dimethylammonium Chloride and Maleamic Acid Derivatives
Author(s) -
Fechner Mabya,
Koetz Joachim
Publication year - 2011
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201100532
Subject(s) - potentiometric titration , chemistry , copolymer , polymer chemistry , ammonium chloride , isoelectric point , acid–base titration , chloride , titration , organic chemistry , polymer , ion , enzyme
Abstract Strongly alternating copolymers (PalH, PalPh, PalPhBisCarb) composed of N , N ′‐diallyl‐ N , N ′‐dimethyl‐ammonium chloride (DADMAC) and maleamic acid derivatives (MAD) are synthesized by a water‐based free radical copolymerization using 4,4‐azobis(4‐cyanovaleric acid) (V501) as the initiator. The structure of the copolymers is verified by 1 H‐NMR, elemental analysis, and thermogravimetric measurements, and the physicochemical properties are investigated by viscometric and potentiometric techniques. Potentiometric titration curves show that the acidity of the carboxylic groups strongly depends on the degree of dissociation and the ionic strength. Since all copolymers behave as polycations at low degree of dissociation, a transition from an extended chain to a coil conformation can be identified by reaching the isoelectric point (IEP).