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Dielectric Relaxation of Poly(ester‐ block‐ amide) Multiblock Copolymers
Author(s) -
Majszczyk Jerzy,
Słonecki Jerzy,
Kozłowska Agnieszka
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010401)202:7<1207::aid-macp1207>3.0.co;2-7
Subject(s) - copolymer , glass transition , polymer chemistry , dielectric , materials science , crystallinity , relaxation (psychology) , amorphous solid , condensation polymer , amide , polymer , atmospheric temperature range , chemical engineering , chemistry , organic chemistry , composite material , thermodynamics , psychology , social psychology , physics , optoelectronics , engineering
A series of poly(ester‐ block ‐amide)s, composed of crystallized sequences of poly(butylene terephthalate) (PBT) and an amorphous, aliphatic oligoamide (PA 36.6) obtained by the reaction of diamines and dimerized fatty acids, has been synthesized by polycondensation in the melt. The dielectric properties of these multiblock copolymers have been investigated as a function of temperature and PBT/PA ratio in the frequency range from 5·10 2 to 10 6 Hz. The melting and glass transition temperatures as well as the degree of crystallinity were characterized by means of DSC. The dielectric properties vary with temperature due to two relaxation processes: a) the β‐relaxation process, associated with the local motion of polar groups attached to the soft and hard segments of the copolymer chain, and b) the α‐relaxation process, associated with long‐range molecular motions near the glass‐transition temperature. This behaviour is discussed by means of the Havriliak‐Negami analysis.