Open AccessInfluence of thermal history on the mechanical properties of poly(ether ketone ketone) copolymers
Author(s) -
Choupin Tanguy,
Debertrand Louis,
Fayolle Bruno,
Régnier Gilles,
Paris Christophe,
Cinquin Jacques,
Brulé Benoît
Publication year - 2019
Publication title -
polymer crystallization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.443
H-Index - 9
ISSN - 2573-7619
DOI - 10.1002/pcr2.10086
Subject(s) - ketone , copolymer , ether , polymer chemistry , materials science , polymer science , chemistry , organic chemistry , polymer
Since poly(ether ketone ketone) (PEKK) is a good candidate as a matrix for composite structural parts, the mechanical properties of PEKK copolymers prepared from diphenyl ether, terephthalic acid (T), and isophthalic acid (I) with different T/I ratios were assessed at room temperature and above their glass transition temperature depending on the thermal history during processing. The influence of cooling conditions and macromolecular modifications at high exposure temperatures was investigated. Results show that modulus and yield properties for a given testing temperature follow a master curve driven mainly by crystallinity regardless of the PEKK copolymers. By modifying PEKK during exposures at 400°C, which leads to branching mechanisms before crystallization, it is shown that modified PEKKs follow the master curve, thus confirming the predominant role of crystallinity in small deformation properties. However, for some morphologies, depending on the crystallization conditions such as cold or melt crystallization, a slight deviation is observed from the global master curve.