New associative EHEC-g-PAam copolymers: Their syntheses, characterization, and rheological behavior

Abstract

The syntheses and rheological behavior of ethyl hydroxyethyl cellulose (EHEC)-based graft-copolymers were studied. Copolymers were prepared by grafting EHEC with acrylamide (Aam) via reversible addition fragmentation chain transfer (RAFT) polymerization. Hydroxyl groups of EHEC were esterified with a carboxylic acid functional chain transfer agent (CTA) to prepare EHEC-macroCTAs with different degrees of substitution. EHEC-macroCTAs were characterized by ATR-FTIR, 13C NMR, and SEC, and elemental analysis was used to quantify the degree of CTA substitution. EHEC-macroCTAs with different degrees of substitution were copolymerized with acrylamide by “grafting from” technique. Formation of new cellulose-based copolymers was comprehensively confirmed by 1H NMR, ATR-FTIR, and SEC measurements. Further, the associations of EHEC-g-PAam copolymers in water were studied at various concentrations and temperatures by means of UV–vis spectroscopy, fluorescence spectroscopy, and rheological measurements. The results indicate that copolymers have both intra and intermolecular association in water depending on the amount of grafts. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1869–1879, 2009