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Dielectric relaxation behavior of poly(acrylonitri1e-co-methacrylonitrile) microcapsules dispersed in a silicone matrixThe dielectric relaxation behavior of poly(acry1onitrile-co-methacrylonitrile) dispersed in a cured polydimethyl siloxane (PDMS) matrix as microcapsules was investigated over multiple thermal cycles and at varying concentrations. The copolymer microcapsules contained an isopentane core. In the PDMS matrix this copolymer displayed a pronounced relaxation signal at temperatures above the glass transition of the copolymers due to Maxwell-Wagner-Sillars (MWS) relaxation. The mechanism of MWS relaxation interpreted by the Havriliak-Negami and Kohlrausch-Williams-Watts relaxation functions was found to be very similar to previous studies of neat polyacrylonitrile and its copolymer. The activation energy of the relaxation decreased over successive thermal cycling coincident with a decreasing strength of the relaxation. These observations were attributed to the decreasing concentration of nitrile groups due to intramolecular cyclizations.
Document ID
20060056287
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
Authors
Park, Taigyoo
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
O'Brien, Emmett
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Lizotte, Jeremy R.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Glass, Thomas E.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Ward, Thomas C.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Long, Timothy E.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Leo, Donald J.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Publication Information
Publisher: Elsevier Science Publishers Ltd.
Subject Category
Inorganic, Organic And Physical Chemistry
Funding Number(s)
CONTRACT_GRANT: NAG1-03026
CONTRACT_GRANT: NAG1-03052
Distribution Limits
Public
Copyright
Other

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