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Characterization of morphology in chemically modified styrene‐ b ‐(ethylene‐ co ‐butylene)‐ b ‐styrene by solid‐state nuclear magnetic resonance
Author(s) -
Collar Emilia P.,
GarcíaMartínez Jesús M.,
Garrido Leoncio
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.27242
Subject(s) - copolymer , maleic anhydride , materials science , styrene , polymer chemistry , reactive extrusion , spin diffusion , grafting , phase (matter) , proton nmr , relaxation (psychology) , ethylene , plastics extrusion , polymer , diffusion , chemistry , composite material , organic chemistry , thermodynamics , psychology , social psychology , physics , catalysis
Multiphase triblock styrene‐ b ‐(ethylene‐ co ‐butylene)‐ b ‐styrene (SEBS) copolymers chemically modified with maleic anhydride (MAH) in the presence of a radical initiator by reactive extrusion were studied by solid‐state 1 H‐NMR and 13 C‐NMR. In the experiments performed, the concentrations of MAH and initiator were kept constant, whereas the temperature profile in the extruder was varied. Samples with known extents of grafting and crosslinking were analyzed with NMR with techniques based on proton spin diffusion to investigate the microphase structure of the modified copolymers. The 13 C‐NMR results show that the size of the rigid domains was about 15 nm and was not significantly changed by the modification. Alterations in the rubbery phase were illustrated by measured changes in proton spin‐spin ( T 2 ) relaxation times. The fraction of protons having intermediate mobilities increased slightly in modified SEBS with respect to that observed in unmodified copolymers. These results were found to be independent of the extruder temperature profiles used, at least in the range studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008