A model of "living" active centers in the solid phase has been developed, which are the complexes of a traditional active center (radical or ion) with a carrier of excessive free volume in solids, the structural defect (vacancy, polyvacancy, dislocation, crack). This model for the first time successfully explained the most nontrivial kinetic peculiarities of the solid phase polymerization.Key words: solid phase polymerization, traditional and "living" active centers in the solid phase, acrylonitrile.Study of polymerization in the solid phase became sys tematic in the late 1950s. The purpose of such works was the preparation of an ordered stereoregular polymer from the ordered molecules of the corresponding monomer in the crystal state. Unfortunately, in most cases it was im possible to confirm the expected effect. At the same time, the initial experimental studies of the solid phase poly merization kinetics proved extremely valuable from the point of view of fundamental science, since they could not be placed in the framework of then existing classic con cept on the kinetics of chain processes 1-6 and for a long time did not have satisfactory explanation.In the present work, using a solid phase polymeriza tion as an example we developed the concepts of mecha nism of the solid phase chain processes from position of activating part of the excessive free volume carriers, viz., the structural defects of the matrix (vacancies, polyvacan cies, dislocations, cracks), in carrying out these processes.Consideration of nontrivial kinetic peculiarities of the solid phase polymerization was performed on a specific model system, solid acrylonitrile, for which the most com plete set of experimentally determined kinetic parameters has been published. 7-9 Consideration of the active in volvement of these mobile defects into the process of the solid phase polymerization is an important point of the approach developed.
The model of "living" active centersA characteristic feature of the solid phase processes and, in particular, the solid phase polymerization is the low translational and orientational mobility of traditional active centers (TAC) (radicals and ions) in such process es, especially at reduced temperatures. At 77 K, the trans lational mobility of TAC is that low that usually, with rare exceptions, 10 results in the absence of both the termina tion and the growth of polymeric chains during the radia tion initiation of the solid phase polymerization at such temperature. This allows one to relatively easy determine one of the polymerization constants, the process initiation rate constant (k i ), the radiation chemical yield of tradi tional active centers.The solid phase post polymerization initiated in such a way is seldom to observe at temperatures Т < 110 К. 7,11 For the most monomers studied, the noticeable rates of the solid phase post polymerization are registered at Т > 160 К, 12-14 and in solid acrylamide even at consider ably higher temperatures (>280 К). 8, 15 It should be noted that due to the possibility of uneve...
