Authors Lang, M. ; Müller, T.
Title Analysis of the gel point of polymer model networks by computer simulations
Date 13.01.2020
Number 57124
Abstract The gel point of end-linked model networks is determined from computer simulation data. It is shown that the difference between the true gel point conversion, pc, and the ideal mean field prediction for the gel point, pc,id, is a function of the average number of cross-links per pervaded volume of a network strand, P, and thus, exhibits an explicit dependence on junction functionality, f. In contrast, the amount of intramolecular reactions at the gel point is independent of f in a first approximation and exhibits a different power-law dependence on the overlap number of elastic strands as compared to the gel point delay, pc – pc,id. Therefore, pc – pc,id cannot be predicted from intramolecular reactions and vice versa in contrast to a long standing proposal in the literature. Instead, the main contribution to pc – pc,id for P > 1 arises from the extra bonds needed to bridge the gaps between giant molecules separated in space and scales roughly · (P – 1)-1/2. Further corrections to scaling are due to nonideal reaction kinetics, composition fluctuations, and incompletely screened excluded volume, which are discussed briefly.
Publisher Macromolecules
Wikidata Q105744740
Citation Macromolecules 53 (2020) 498-512

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