A WAXD and solid-state NMR study on cocrystallization in partially cycloaliphatic polyamide 12.6-based copolymers

B. Vanhaecht, R. Willem, M. Biesemans, B. Goderis, M. Basiura, P.C.M.M. Magusin, I.P. Dolbnya, C.E. Koning

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)

Abstract

To study the influence of the stereochem. on the possibility of cocrystn. of linear and cyclic aliph. residues in copolyamides, a series of copolyamides 12.6/12.1,4-cyclohexanedicarboxylic acid with variable compns. were synthesized. From solid-state NMR studies it could be deduced that cis-1,4-CHDA is present in the amorphous regions whereas the trans residues are located in both the cryst. and the amorphous phase. WAXD patterns confirm the presence of trans-1,4-CHDA inside the crystals and reveal that the cycloaliph. ring is most likely oriented in a direction perpendicular to the crystal sheets that contain the hydrogen bonds. As a result, the intersheet distance is increased compared to that of polyamide 12.6. Furthermore, the rings prevent the genesis of a pseudohexagonal phase above the Brill temp. Exceptionally, crossing rather than merging of the (100) and the combined (010)-(110) WAXD reflections is obsd. with increasing temp., indicating that the intersheet distances increase and become larger than the interchain distances within the hydrogen-bonded sheets before the crystals start to melt. Incorporation of trans-1,4-CHDA residues into polyamide 12.6 leads to higher melting temps., pointing at cocrystn. in terms of a solid soln. rather than as defects. In contrast, a slight m.p. depression is obsd. for copolymers with predominately cis-1,4-CHDA residues. [on SciFinder (R)]
Original languageEnglish
Pages (from-to)421-428
JournalMacromolecules
Volume37
Issue number2
DOIs
Publication statusPublished - 2004

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