Arm Retraction Potential of Branched Polymers in the Absence of Dynamic Dilution

DANIEL A. VEGA; LEOPOLDO R. GÓMEZ; LEANDRO E. ROTH; JORGE A. RESSIA; MARCELO A. VILLAR; ENRIQUE M. VALLÉS

PHYSICAL REVIEW LETTERS

Año: 2005 vol. 95 p. 1660021 - 1660024

0031-9007

We study the stress relaxation of model polymer networks containing low contents of star shaped andlinear dangling polymers. As compared with their melts, the behavior of star and dangling polymers leadsto a dynamic response with unprecedented large relaxation times. By comparing data of star melts withthose corresponding to stars and dangling chains residing in polymer networks, we were able to identifythe effects of dynamic dilution clearly. Since in polymer networks the dynamic dilution effect issuppressed, we were able by the first time to experimentally test the validity of the potential for armretraction proposed by Pearson and Helfand.