Equilibrium ring concentrations and the statistical conformations of polymer chains Part 15. Large cyclics in liquid sulfur

A rotational isomeric state (RIS) model for polymeric sulfur chains has bee n used to calculate the concentrations of cyclics S-x with x > 8 in liquid sulfur below the critical polymerization temperature. The cyclics S-12, S-1 8 and S-20 were predicted to be present in the largest amounts in agreement with experiment. Other cyclics such as S-11 and S-13 were predicted to be absent from the melt and they are known to be physically present in only tr ace amounts. Variations of structural and statistical weight parameters in the RIS model are explored. The original model is shown to give the best ag reement with all experimental information. (C) 1999 Elsevier Science Ltd. A ll rights reserved.