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A thermomechanical investigation of highly cold‐drawn polycarbonate
Author(s) -
Kato T.,
Kambe H.
Publication year - 1978
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.1978.070220701
Subject(s) - polycarbonate , glass transition , polymer , relaxation (psychology) , materials science , thermodynamics , activation energy , polymer chemistry , melting temperature , shrinkage , composite material , chemistry , physics , psychology , social psychology
A new technique detecting molecular motions in drawn polymers was applied to highly cold‐drawn polycarbonate of bisphenol A. It is shown that the sample exhibits thermal shrinkage in three steps with the temperature increase up to above the glass transition temperature. The molecular relaxation at the highest temperature is due to the glass transition. The other two molecular motions at the lower temperature are those of main chain in the glassy state and they correspond to the molecular motions as revealed in dielectric measurement by Sacher. 1 By using the general theory of the thermal analysis by Ozawa, 2 the apparent activation energies of these molecular motions were obtained: for the highest temperature 110 kcal/mole, and for the lowest temperature, 33.5 kcal/mole. The impact strength and the cold workability of this polymer are also discussed in relation to these molecular motions.