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Chain segment ordering in uniaxially strained networks: A deuterium NMR investigation
Author(s) -
Deloche Bertrand
Publication year - 1993
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19930720105
Subject(s) - deuterium , polydimethylsiloxane , polymer , chain (unit) , materials science , deuterium nmr , orientation (vector space) , chemical physics , crystallography , chemistry , physics , nanotechnology , composite material , mathematics , geometry , quantum mechanics , astronomy
The deuterium NMR ( 2 H‐NMR) is used for probing the chain segment orientation in polymer networks under uniaxial stress. The method is based on the observation of an incomplete time averaging of quadrupolar interactions affixed to deuterated segments. The samples are end‐linked polydimethylsiloxane networks. The 2 H‐NMR experiments are performed either on labelled network chains or an labelled probe polymer chains dissolved in the network. The basic results are the following: — The induced uniaxial order is related to a uniaxial dynamics of chain segments around the direction of the applied constraint. — A permanent orientation is observed on free polymer chains dissolved in the deformed networks. — The mean degrees of orientational order induced along short and long chains in bimodal networks are the same. These experimental facts appear as evidences for cooperative orientational couplings between chain segments in the deformed networks.