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

Abstract

In this “Reply” the authors discuss previously published theoretical and experimental results indicating flaws in the Jacobson-Stockmayer theory of reversible polycondensations, with special regard to a pertinent “Comment” of Prof. R. Szymanski.

Reversible polycondensations outside the Jacobson–Stockmayer theory and a new concept of reversible polycondensations

“…Critique of part of the JS-theory was recently published by the authors 5,6 who demonstrated that formation of cyclic oligomers and polymers does not only result from "back-biting" but also from end-to-end (ete) cyclization, which is in contrast to the assumption of J + S. However, previous results and the results presented below demonstrate that ete-cyclization is a very efficient process. Moreover, it is unproven that the cycles indirectly detected by J + S (mass spectrometry and NMR spectroscopy did not exist at that time) mainly or exclusively result from back-biting.…”

“…Both aspects of the JS theory overlap, of course, but are not identical. The critique of the authors in their previous publications 5,6 and in the present work is exclusively directed against the JS-hypothesis of revPOCs.…”

Simple and General Approach for Reversible Condensation Polymerization with Cyclization

“…These problems and other difficulties for estimating the weight fraction of rings were quickly recognized and they are still discussed controversially in the literature; see refs − for the most recent contributions. Not surprisingly, during the past decades, several authors have tried to improve the weak points of the JS approach.…”

About the Influence of (Non‐)Solvents on the Ring Expansion Polymerization of l‐Lactide and the Formation of Extended Ring Crystals

“…Synthesis and characterization of cPLA have rapidly increased over the past 15 years. [ 7–40 ] The polymerization methods may be subdivided into two categories, first, polymerizations obeying the ROPPOC definition, meaning ring‐opening polymerization with simultaneous polycondensation (including cyclization), [ 41 ] and second, ring‐expansion polymerization (REP) using covalent cyclic catalysts. [ 42 ] The present work is based on REPs catalyzed by two cyclic tin compounds, 2,2‐dibutyl‐2‐stanna‐1,3‐dithiolane (DSTL) and 2‐stanna‐1.3‐dioxa‐4,5,6,7‐dibenzazepine (SnBiph, see Scheme ), because these catalysts have proven in recent REPs conducted in bulk, that they may yield medium and high molecular weight cPLA with average number molecular weights ( M n ) up to 200 000 and average weight molecular weights ( Mw ) up to 400 000) along with extraordinarily high melting temperatures ( T m ) and melting enthalpies (Δ H m ).…”