Theory of equilibrium copolycondensation

Development of a quantitative theory of polycondensation

“…The Markov chain parameters are related to the constants of the elementary reactions and to the composition of the initial monomer mixture. A similar result was reported for an ideal equilibrium polycondensation [154]. The identity of the results for these two extreme process modes shows that any statistical characteristic of the chemical structure of the products may be calculated by the Markov chain formalism for any intermediate regime of an ideal copolycondensation.…”

“…In the framework of such a simplified FSSE model, general regularities have been revealed of the dependence of K M on stoichiometric and kinetic parameters, and simple analytical expressions for K M have been derived at different limiting values of these parameters [151]. Analogous results have been reported [154] for the equilibrium regime of interbipolycondensation in which the independence of intermonomer groups was shown to be a sufficient condition for obtaining a random copolymer.…”

“…When developing the quantitative theory of an equilibrium copolycondensation it was shown [154] that the extension of the model by incorporating any order 'substitution effect' does not disturb the Markovian character of the sequence distribution. The same authors employed different versions of the FSSE model to calculate the parameters of the corresponding Markov chain in the limiting case when the average length of a macromolecule P N tends to infinity.…”

“…Finding an unambiguous correspondence between the configurations of copolymer molecules and the realizations of a Markov chain made it possible to obtain simple asymptotic relationships at large P N for the composition distribution of polycondensation copolymers [154,164,165]. In the case of interbipolycondensation, these distributions are Gaussian [154,164,165], with parameters depending only on three quantities: P N ; the composition of the initial monomer mixture and K M : An analysis of these dependencies reveals that the composition distribution becomes narrower as P N grows or the average length of blocks in the copolymer decreases with increasing K M :…”

Step Copolymerization

“…has applied these principles to the step copolymerization of the system AA, BB, CC where BB does not react with CC; in such a system six types of polymeric chains exist classified with respect to their end groups: A",A, B",B, C",C, A",B, A",C, B",C. Each has a distribution of chain lengths (6) which can be obtained by the reasoning which leads to equation (3). has applied these principles to the step copolymerization of the system AA, BB, CC where BB does not react with CC; in such a system six types of polymeric chains exist classified with respect to their end groups: A",A, B",B, C",C, A",B, A",C, B",C. Each has a distribution of chain lengths (6) which can be obtained by the reasoning which leads to equation (3).…”