Stereochemistry driven cocrystallisation phenomena in partially cycloaliphatic polyamides
Koning, C × Vanhaecht, B Willem, R Biesemans, M Goderis, Bart Rimez, B #
Wiley-v c h verlag gmbh
Macromolecular symposia vol:199 pages:431-442
Two series of isomeric copolyamides were synthesised, viz. polyamides 12.6 for which the adipic acid residues were partially replaced by cis/trans-1,4-cyclohexanedicarboxylic acid (1,4-CHDA), and polyamides 4.14 for which the 1,4-diaminobutane residues were partially replaced by cis/trans-1,4-diaminocyclohexane (1,4-DACH). A careful DSC and WAXS analysis learned that only the trans isomers of both 1,4-DACH and 1,4-CHDA are incorporated into the crystalline phase. During DSC analysis, an intitial high trans content is preserved in the case of the non-isomerising 1,4-DACH, whereas the 1,4-CHDA residues gradually isomerise from a high initial trans content to a significanly lower trans content. Since these cis residues are not incorporated into the crystalline domains, the lower second heating melting points of the 1,4-CHDA-based copolyamides in comparison with 1,4-DACH-based copolyamides, having similar cycloaliphatic monomer contents, can be understood.