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Radical polymerization of 2-, 3-, and 4-chlorostyrenes (ClSts) was investigated with benzoyl peroxide (BPO) as an initiator, in the presence of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO). The polymerization was performed in bulk for 3.5 h at 95ЊC and then continued for a defined time at 125ЊC to give the corresponding poly(ClSt)s with narrow polydispersity in high yield. It was found that the polymerization proceeded in accordance with a living mechanism in all cases, because the molecular weight of the resulting polymers was proportional to the conversion, and inversely proportional to the initial concentration of MTEMPO. Furthermore, the polymers obtained from 2-and 3-ClSts quantitatively act as initiators for the polymerization in the living radical manner, of styrene to give the corresponding block copolymers, except for poly(4-ClSt). The thermal stability of the living poly(ClSt)s was found to decrease in the order of 2-ú 3-ú 4-ClSt on the basis of the results of their postpolymerizations.

ABSTRACT:Two polyamide 6 (PA6) radical initiators (PA6ini), AI and AlA types (A: PA6 segment, I: azo group), were prepared from 4,4'-azobis-2-cyanopentanoyl chloride and PA6 prepolymers having controlled average molecular weights. Various PA6-hlock-vinyl polymers were synthesized by radical polymerizations of vinyl monomers, such as styrene, methyl methacrylate (MMA), butyl methacrylate, hydroxyethyl methacrylate and vinyl acetate (VAc) using PA6inis. The polymerizations of MMA proceeded homogeneously in phenol/methanol (4,01/1,01), formic acid and 2,2,2-trifluoroethanol. The overall initiation efficiency of PA6ini (AI type) was 0.11 for the polymerization of MMA in formic acid at 60oC for 24h. Poly(MMA) in the polymer synthesized using PA6ini was dependent on concentration, molecular weight and type of PA6ini. PA6-block-poly(VAc) was synthesized in 2,2,2-trifluoroethanol (TFE), but not in phenol/methanol (4,01/1,01).KEY WORDS Polyamide 6 Radical Initiator / Macroazoinitiator / Block Copolymer / RadicalPolymerization I Vinyl Monomers I Polyamide 6 (PA6) has many industrial applications. Block copolymers from P A6 and other polymers, such as vinyl polymers, polyethers, polyimides and polyesters, were synthesized, expecting new properties.

Radical polymerization of 2‐, 3‐, and 4‐chlorostyrenes (ClSts) was investigated with benzoyl peroxide (BPO) as an initiator, in the presence of 4‐methoxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (MTEMPO). The polymerization was performed in bulk for 3.5 h at 95°C and then continued for a defined time at 125°C to give the corresponding poly(ClSt)s with narrow polydispersity in high yield. It was found that the polymerization proceeded in accordance with a living mechanism in all cases, because the molecular weight of the resulting polymers was proportional to the conversion, and inversely proportional to the initial concentration of MTEMPO. Furthermore, the polymers obtained from 2‐ and 3‐ClSts quantitatively act as initiators for the polymerization in the living radical manner, of styrene to give the corresponding block copolymers, except for poly(4‐ClSt). The thermal stability of the living poly(ClSt)s was found to decrease in the order of 2‐ > 3‐ > 4‐ClSt on the basis of the results of their postpolymerizations. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2371–2378, 1997

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