Contribution of Linear Guest and Structural Pendant Chains to Relaxational Dynamics in Model Polymer Networks Probed by Time-Domain 1H NMR

F. CAMPISE; L. ROTH; R. H. ACOSTA; M. A. VILLAR; E. M. VALLES; G. A. MONTI; D. A. VEGA

MACROMOLECULES

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 49 p. 387 - 394

0024-9297

A series of end-linked polymer networks with varying contents of linear guest chainswere investigated through swelling and time?domain NMR temperature dependent ex-periments. Taking advantage of the thermo-rheological simplicity of polydimethyl-siloxane polymers, time?temperature superposition (TTS) was employed to expandthe characteristic time scales of NMR exploration by about two orders of magnitude.A comparison between swelling data and tube model predictions reveals that NMRcaptures the dominant features of the equilibrium and dynamic properties of defectstrapped in slightly crosslinked, entanglement-dominated polymer networks. As high-temperature experiments ensures a complete relaxation of the guest linear chains onthe millisecond time scale of the NMR experiments, an accurate description of thenetwork architecture can be provided. Contents of guest chains determined by NMRwere found to agree within a 1wt.% accuracy with data of swelling experiments.