Effect of crystal size on the reaction kinetics in the solid-state polymerization of 1,6-Di(N-carbazolyl)-2,4-hexadiyne

The mechanism of a phase transition upon the polymerization of 1,6-di (N-ca rbazolyl)-2,4-hexadiyne crystals was determined; the process occurs through an intermediate two-phase state of the polymerizing system in which polyme r phase regions nucleate and grow within the monomer phase without damaging the lattice necessary to form a polydiacetylene crystal. In contrast to la rge monomer crystals of a size of about 0.3-0.1 mm, submicrometer-sized cry stals in a sublimed film undergo homophase polymerization by a gradual rear rangement of the monomer to the polymer lattice. The polymerization kinetic s of microcrystals were determined, including the features of their rearran gements in the course of the reaction. The effect of crystal size on the re action is discussed in relation to the size of a strain region surrounding a polymer chain in the lattice of a polymerizing crystal.