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Thermal properties and dielectric relaxation of a multi‐component poly(ether‐ co ‐amide) based on polyamide‐12
Author(s) -
Yoshiba Kazuto,
Satomi Tsuyoshi,
Ishii Tomohiro,
Dobashi Toshiaki
Publication year - 2016
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.5177
Subject(s) - polyamide , materials science , glass transition , dynamic mechanical analysis , amorphous solid , dielectric , polymer chemistry , thermal analysis , relaxation (psychology) , polymer , composite material , chemistry , organic chemistry , thermal , thermodynamics , psychology , social psychology , physics , optoelectronics
DSC, dielectric relaxation and dynamic mechanical thermal analysis (DMTA) were carried out on two multi‐component poly(ether‐ co ‐amide) samples having different weight ratios of polyamide prepared by condensation polymerization with 12‐aminododecanoic acid, adipic acid and polyetherdiamine consisting of poly(tetramethylene oxide) and poly(propylene oxide). The melting temperature was lowered by an increase in the weight ratio of the polyamide segment. Three relaxation modes, α′, α s and β, were found from dielectric relaxation measurements in different temperature ranges. The high temperature relaxation mode, α′, has a large dielectric constant, which disappears at the melting temperature of the polyamide crystal in the sample. The relaxation times for the segmental motion, α s , were different for the samples, which is attributed to the difference in the composition of the uncrystallized polyamide segments in the amorphous domain. The glass transition temperature estimated from DMTA is located between those of constituting polymers. On the other hand, the activation energy of β‐mode observed at low temperatures is the same for samples with different polyamide ratios, which is attributed to the local motion of the polyether segments. The uncrystallized polyamide segments are miscible with the polyether segments, which results in a lowering of the glass transition temperature of the amorphous domain and enlarges the temperature range of the rubber state of the copolymer due to the high melting temperature of the polyamide segments. © 2016 Society of Chemical Industry