Synthesis of cyclic polymers and flaws of the Jacobson–Stockmayer theory

Abstract

The results of this study show that even at the highest initial monomer concentration (IMC) complete cyclization of polymer chains can be achieved at 100% conversion.

Reply to the comment on “synthesis of cyclic polymers and flaws of the Jacobson-Stockmayer theory” by R. Szymanski

“…Reply to the comment on "synthesis of cyclic polymers and flaws of the Jacobson-Stockmayer theory" by R. Szymanski In a recent publication the authors 1 have presented theoretical and experimental results indicating that the Jacobson-Stockmayer (JS) theory 2,3 does not provide a correct description of reversible polycondensations for all polymers and for high conversions (e.g. polycondensation in bulk).…”

“…The experimental evidence was later contributed by Kricheldorf and coworkers. 10,11 The existence of ete-cyclization in reversible polycondensation was not only proven by numerous experiments, 1 it is a consequence of straightforward logic. Firstly, when the end groups of oligomers and polymers are reactive enough to undergo intermolecular condensation (i.e.…”

“…The only parameter which can prevent ete-cyclization is extreme chain stiffness, but this property also hinders cyclization by back-biting, and stiff chains are excluded from the JS theory as outlined by J + S themselves. 2 Secondly, Kricheldorf et al have demonstrated by MALDI-TOF mass spectrometry 1,12 that cycles up to a degree of polymerization (DP) of 90 exist in nylon-6 prepared by reversible polycondensation of ε-aminocaproic acid or its mixtures with ε-caprolactam. In poly(l-lactide)s prepared via ringopening polycondensation combined with simultaneous polycondensation (ROPPOC) cycles up to DP 120 were identified.…”

“…When the electrophilic end group is more reactive than an amide or ester group in the chain (as it is typical for the experiments in ref. 1 and in almost all successful polycondensations), the vast majority of cycles will then be formed by ete-cyclization. When the reactivities of electrophilic end groups and bonds in the chain are similar at least part of the cycles will be formed by ete-cyclization.…”

“…The meaning of 100% conversion and the consequences for the understanding of reversible step-growth polymerizations have been discussed 1 and are here discussed on the basis of eqn (1)- (3). Eqn (1) is the definition of the conversion ( p) for normal step-growth polymerizations.…”