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4711524 
Journal Article 
Reactivity Ratios and Sequence Distribution Characterization by Quantitative C-13 NMR for RAFT Synthesis of Styrene-Acrylonitrile Copolymers 
Alam, MdM; Peng, Hui; Jack, KS; Hill, DJT; Whittaker, AK 
2017 
Yes 
Journal of Polymer Science. Part A, Polymer Chemistry
ISSN: 0887-624X
EISSN: 1099-0518 
WILEY 
HOBOKEN 
55 
5 
919-927 
English 
WOS:000393883900016 
The kinetics and reactivity ratios of styrene-acrylonitrile (SA) copolymerization have been studied extensively in bulk and in a variety of solution media using conventional free radical polymerizations (FRPs). Due to the significant difference in the two reactivity ratios for this monomer pair, at certain feed ratios the copolymers display composition drift with conversion due to monomer depletion. In this study, the kinetics of SA copolymerization using Reversible Addition-Fragmentation Chain Transfer (RAFT) has been studied in bulk at 80 degrees C. The reactivity ratios for the terminal model were calculated from the comonomer sequence distributions for the RAFT process at low conversion for nine different compositions and found to be in the same range as those reported for conventional FRP of SA. The changes in the composition and sequence distribution with conversion were studied for three feed compositions. The copolymers show compositional drift with conversion, except at the azeotropic composition, and match the predictions from the reactivity ratios obtained at low conversion. From quantitative C-13 NMR the triad distributions of these copolymers were estimated and found to match the predicted triad distributions as conversion increased. (c) 2017 Wiley Periodicals, Inc. 
13C NMR; copolymerization; RAFT; reactivity ratios; sequence distribution