Comparison of Gelation in the Free‐Radical Polymerization of Triallyl Isocyanurate and its Isomer Triallyl Cyanurate

Free‐radical polymerizations of triallyl cyanurate (TAC) and its isomer triallyl isocyanurate (TAIC) were conducted in bulk at 60°C. In the polymerization of TAIC, gelation occurred at 12.4% conversion, quite early compared to 21.3% for TAC. The primary chain length of TAIC polymer, as estimated from GPC‐LALLS measurements, was quite high. Although TAIC undergoes more cyclic polymerization than TAC, its greater primary chain length causes it to gel at a lower conversion. On the other hand, the difference in the rate of polymerization between TAC and TAIC was quite small compared to that of the primary chain length. These results are discussed mechanistically in connection with the degradative chain transfer characteristics of the polymerization of allyl compounds.