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Retardation and relaxation behaviour of poly (ether‐block‐amide)s (PEBA) copolymers by thermally stimulated creep (TSCr) and current (TSCu)
Author(s) -
Demont Philippe,
Chatain Daniel,
Lacabanne Colette,
Glotin Michel
Publication year - 1989
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.19890250116
Subject(s) - glass transition , materials science , relaxation (psychology) , amorphous solid , creep , copolymer , melting point , polymer chemistry , phase (matter) , polyamide , thermodynamics , polymer , composite material , crystallography , chemistry , organic chemistry , physics , psychology , social psychology
The retardation and relaxation behaviour of poly(ether‐block‐amide)s PEBA copolymers was investigated as a function of hard polyamide sequence length by using thermally stimulated creep (TSCr) and Current (TSCu). Two primary TSCr and TSCu peaks, called ß PE and ß PA were observed in the temperature range 150–300 K. The “low temperature” peak ß PE was characterized by a peak position T ß PE which depends poorly upon hard segment content as the corresponding DSC glass transition temperature Tg PE . The peak position Tß PA of the “high temperature” relaxation showed a progressive shift towards higher temperatures as the hard segment average length was increased as it is observed in series of pure polyamide oligomers. So, complex spectra suggest that an amorphous phase separation occurs in PEBA copolymers. The TSCr ß PE and ß PA modes were analysed by thermal sampling method (TS). The elementary TSCr processes isolated in the ß PE and ß PA distributed retardation modes were characterized by retardation times following a compensation law. The comparison of activation and compensation parameters confirmed the existence of a biphasic amorphous phase in PEBA. In TSCr spectra, an additional peak, noted α, is observed at a temperature close to the DSC melting point T mPE of the poly(tetramethylene glycol) segments.