Contribution of Entanglements to Polymer Network Elasticity

CAMPISE, F.; AGUDELO, D. C.; ACOSTA, R. H.; VILLAR, M. A.; VALLÉS, E. M.; MONTI, G. A.; VEGA, D. A.

MACROMOLECULES

AMER CHEMICAL SOC

Lugar: Washington; Año: 2017 vol. 50 p. 2964 - 2972

0024-9297

Trapped entanglements, cross-linker functionality,and elastically effective chains are the sources of elasticity ofpolymer networks and gels. However, despite more than 80years of theoretical and experimental research in this field, stilllittle is known about their relative contribution to networkelasticity. In this work, we use double quantum nuclear magneticresonance (DQ NMR) experiments to characterize the elasticityof model polymer networks prepared with cross-linkers of mixed functionality and control of structural defects. An orderparameter that condensates the elastic response within the theoretical framework of the entangled phantom theory for rubberelasticity was identified. Standard lore dictates that low molecular weight precursors for the elastically active chains leads to anegligible contribution of trapped entanglements. Here we show that the contribution of trapped entanglements may equal thecontribution coming from elastically active material and that it is independent of network topology.