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. VALLÉS; 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 with9 varying contents of linear guest chains were investigated10 through swelling and time-domain NMR temperature depend-11 ent experiments. Taking advantage of the thermorheological12 simplicity of polydimethylsiloxane polymers, time−temper-13 ature superposition (TTS) was employed to expand the14 characteristic time scales of NMR exploration by about 215 orders of magnitude. A comparison between swelling data and16 tube model predictions reveals that NMR captures the17 dominant features of the equilibrium and dynamic properties18 of defects trapped in slightly cross-linked, entanglement-19 dominated polymer networks. As high-temperature experi-20 ments ensures a complete relaxation of the guest linear chains on the millisecond time scale of the NMR experiments, an accurate21 description of the network architecture can be provided. Contents of guest chains determined by NMR were found to agree22 within a 1 wt % accuracy with data of swelling experiments.