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

Synthesis of a cellulose supported chain transfer agent and its application to RAFT polymerization

“…2) to determine the degree of substitution (DS; see Experimental Section) and a maximum of 1.6 was observed after 6 days. Although the conversion of hydroxyl groups of HPC into thiocarbonyl thio moieties was only 50% (average DS of 1.5), this is one of the highest reported DS for homogeneous modification of cellulose into macro‐CTA for RAFT polymerization 21–23…”

“…Stenzel et al21 were the first to report the preparation of trithiocarbonate CTA based on soluble cellulose, hydroxyisopropyl cellulose (HPC), via the Z‐group approach, to obtain polystyrene comb polymers. Recently, Hiltunen et al22 and Fleet et al23 reported similar studies using hydroxypropyl, methyl, and ethyl hydroxyethyl cellulose. In all these studies, some degree of insolubility is observed that results in decrease in the reliability of the characterization methods used.…”

Nanocrystalline cellulose grafted random copolymers of N-isopropylacrylamide and acrylic acid synthesized by RAFT polymerization: effect of different acrylic acid contents on LCST behavior

“…[27][28][29][30][31] Cellulose and its nanocrystalline parts have commonly been used for synthesis of biodegradable based nanocomposites by in situ CRP methods with graing from approach. [32][33][34][35][36][37][38][39][40][41][42][43] Glaied et al reported synthesis of cellulose bers densely graed with poly[2-(meth-acryloyloxy)ethyl]-trimethylammonium chloride through aqueous ATRP. 32 They exploit the hydroxyl groups present on the cellulose surface to attach the ATRP initiator.…”

Tailoring of water‐soluble cellulose‐g‐ copolymers in homogeneous medium using single‐electron‐transfer living radical polymerization

“…More uniform modifications and better control of the degree of substitution are obtained if grafting is performed under homogeneous conditions 35. Homogeneous reaction conditions for preparing cellulose‐based graft copolymers by CRP methods are mostly designed for soluble cellulose derivatives, such as ethyl cellulose,36–39 hydroxypropyl cellulose,40–43 cellulose diacetate,44, 45 methyl cellulose,46 hydroxyethyl cellulose47 and ethylhydroxyethyl cellulose 48. Even though new ways to dissolve cellulose have been developed during the last few decades,49, 50 and the cellulose can be modified homogeneously, cellulose‐ graft ‐copolymers have seldom been prepared homogeneously via CRP methods directly from cellulose.…”