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Strengthening due to interlamellar constraint in oriented syndiotactic styrene– p ‐methyl styrene copolymer
Author(s) -
Pricope D.,
Shinozaki D. M.
Publication year - 2002
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.11250
Subject(s) - copolymer , materials science , differential scanning calorimetry , styrene , melting point , tacticity , glass transition , dynamic mechanical analysis , composite material , modulus , polymer chemistry , polymer , thermodynamics , physics , polymerization
Channel die compression has been used to form highly oriented syndiotactic styrene– p ‐methylstyrene copolymer in the solid state. The highest forming temperatures were at or near the nominal unoriented melting point (247°C). The oriented materials produced at 245 and 220°C were examined by differential scanning calorimetry, wide‐angle X‐ray diffraction, and dynamic mechanical thermal analysis. The measured increases in modulus, which resulted from the forming of the copolymer could be related to the microstructural changes in the material. The analysis of mechanical properties with a simple Takayanagi model showed that the high modulus above the glass transition temperature in oriented samples was at least partly due to an interlamellar constraint of the kind suggested by Arridge and co‐workers. The magnitudes of the constraint factor that were estimated in the modeling process were consistent with the observed microstructural changes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2312–2321, 2002