Controlled free‐radical copolymerization of styrene (S) and butyl acrylate (BA) was achieved by using a second‐generation nitroxide, N‐tert‐butyl‐N‐[1‐diethylphosphono‐(2,2‐dimethylpropyl)] nitroxide (DEPN), and 2,2‐azobisisobutyronitrile (AIBN) at 120 °C. The time‐conversion first‐order plot was linear, and the number‐average molecular weight increased in direct proportion to the ratio of monomer conversion to the initial concentration, providing copolymers with low polydispersity. The monomer reactivity ratios obtained were rS = 0.74 and rBA = 0.29, respectively. To analyze the convenience of applying the Mayo–Lewis terminal model, the cumulative copolymer composition against conversion and the individual conversion of each monomer as a function of copolymerization time were studied. The theoretical values of the propagating radical concentration ratio were also examined to investigate the copolymerization rate behavior. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4168–4176, 2004

Two chemical structural isomers, 2-hydroxyethyl methacrylate and ethyl ␣-hydroxymethyl acrylate, were copolymerized with dimethyl amino ethyl methacrylate in bulk at 50°C with 1.0 ϫ 10 Ϫ2 mol/L 2,2Ј-azobisisobutyronitrile as an initiator. Experiments showed differences in the values of the monomer reactivity ratios due to electronic or steric contributions to the cross-propagation reaction. The homopolymer glass-transition temperature (T g ), along with the intramolecular and intermolecular structure and Johnston's equation, enabled a description of the experimental variations of the copolymer T g .

SYNOPSISEthyl a-hydroxymethylacrylate ( EHMA) was polymerized in a 3 mol/L tetrahydrofuran solution at 50°C, using 2-2' azobisisobutyronitrile as initiator. The kinetic behavior indicates a higher polymerization rate for EHMA than for methyl methacrylate (MMA) . Copolymerization reaction between MMA and EHMA, under the same experimental conditions, was carried out and values of r M M A = 1.264 and r E H M A = 1.285 were found for the reactivity ratios. The comparison of triad sequences as determined from Bernouillian statistic to those calculated from the experimental spliting of 0-methyl and a-methyl 'H-NMR signals of the copolymers confirm the obtained results. 0 1992 John Wiley & Sons, Inc.

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The free‐radical copolymerization of styrene with butyl acrylate was carried out in benzene and benzonitrile at 50°C. Differences between the apparent reactivity ratios determined in this work and those previously reported in bulk indicated noticeable solvent effects. This is explained by a qualitative bootstrap effect. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 60–67, 2000