Radical cyclopolymerization of allyl methacrylate (AMA) was investigated in detail, especially under the specified conditions; that is, above the ceiling temperature for a head‐to‐tail propagation (ΔGht ≥ 0) in the polymerization of methacrylate. Thus the structure of the polymer obtained was examined by 1H‐ and 13C‐NMR and infrared (IR) spectroscopy; no existence of unreacted pendant methacrylyl groups was observed, which suggests that, as a cyclopolymerization mechanism of AMA, intermolecular propagation of growing radicals, followed by intramolecular cyclization or intermolecular propagation of the resulting uncyclized methacrylyl radical, occurs exclusively with methacrylyl group. Temperature dependency of cyclization constant Kc was unusual; Kc increased rapidly at elevated temperatures and no linear relationship of ln Kc vs. 1/T was observed. Five‐membered ring formation was favored at an elevated temperature and diluted monomer concentration. These results are discussed thermodynamically in terms of controlled ring closure in cyclopolymerization.

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Radical polymerization studies on diallyl oxalate (DAO), diallyl malonate (DAM), diallyl succinate (DASu), diallyl adipate (DAA), and diallyl sebacate (DAS) have been conducted kinetically from the standpoint of cyclopolymerization. Benzoyl peroxide was employed as the initiator. The initial overall rate of polymerization, Rp was not proportional to the square root or the first power of the initiator concentration, [I]. But Rp/[I]1/2 and [I]1/2 bore a linear relationship, provided the monomer concentration was kept constant. The residual unsaturation of the polymers decreased with decreasing monomer concentration. The ratio of the rate constant of the unimolecular cyclization reaction to that of the bimolecular propagation reaction of the uncyclized radical, Kc, was evaluated from the above relationship between the residual unsaturation and the monomer concentration at 60°C. The Kc values obtained were 3.6, 3.2, 2.8, 2.5, and 1.2 mole/l. for DAO, DAM, DASu, DAA, and DAS, respectively. The overall activation energies of polymerization were found to be 21.1 (DAO), 24.2 (DAM), 21.7 (DASu), 22.0 (DAA), and 22.2 (DAS) kcal/mole.

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SUMMARY:Radical copolymerizations of diallyl phthalate (DAP), diallyl isophthalate (DAI), and diallyl terephthalate (DAT) with methylallyl benzoate (MABz) have been carried out in bulk a t 60°C, using benzoyl peroxide as initiator.In the copolymerization of DAP with MABz the residual unsaturation of the copolymer decreased with increasing mole fraction of MABz in the feed. I n the case of DAI it was nearly constant, regardless of the molar feed ratio, whereas with DAT it tended to increase with increasing mole fraction of MABz in the feed. These results were interpreted by considering the difference of the mode of cyclization in the case of DAP, DAI, and DAT.The following monomer reactivity ratios yl (of the nncyclized radical), yc (of the cyclized radical) and y2 (of the MABz radical) were estimated on the basis of the cyclocopolymerization mechanism. DAP: 0,84; 0,61; 1,08; DAI: 0,76; 0,52; 1,06. For the copolymerization of DAT with MABz the apparent monomer reactivity ratios based on the general copolymer composition equation were obtained as yl -0,79 and yz = 1,06. ZUSAMMENFASSUNG:Radikalische