Polymerizable tautomers: XII. Polymerization of methyl methacrylate initiated by the binary system of poly(ethyl 3-oxo-4-pentenoate) and cobalt(II) nitrate

The polymerization of methyl methacrylate (MMA) initiated by the binary sys tem of poly(ethyl 3-oxo-4-pentenoate) (PEAA) and cobalt(II) nitrate was kin etically investigated. The kinetic orders of the polymerization are 0.53 an d 1.48 with respect to PEAA and MMA, respectively. These results suggests t hat a PEAA-cobalt(II) nitrate complex participates in the initiation step a nd that MMA is involved both in initiation and propagation of the polymeriz ation. Graft polymer is essentially obtained because PEAA is a polymer cata lyst. The apparent activation energy for the polymerization was evaluated a s 93.7 kJ mol(-1). The energy of decomposition of the PEAA-cobalt(II) nitra te complex was calculated as 147.2 kJ mol(-1) on the basis of the apparent activation energy. This value is comparable to that for azobisisobutyronitr ile. Monomer reactivity ratios r(1) = 0.36 and r(2) = 0.58 were obtained fo r the PEAA-cobalt(II) nitrate catalyzed copolymerization of MMA (M-1) and s tyrene (M-2). (C) 1999 Elsevier Science Ltd. All rights reserved.