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New alternating poly(amide‐ester)S: Synthesis and properties
Author(s) -
Keul Helmut,
Robertz Bernd,
Höcker Hartwig
Publication year - 1999
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19991440106
Subject(s) - materials science , amide , polyamide , polymer chemistry , polymer science , chemistry , organic chemistry
New alternating poly(amide‐ester)s derived from β‐hydroxy acids and α‐amino acids 3a,b or ϵ‐aminocaproic acid 4a‐c were prepared. Two approaches were considered: (i) polycondensation of N‐(β‐hydroxyacyl)‐amino acids 1a,b and 2b,c and (ii) ring‐opening polymerization of cyclic amide‐esters 5a‐c and 6a‐c . For all the linear precursors polycondensation reactions result in oligomers with number average molecular weights lower than 5000. The ring‐opening polymerization of the cyclic precursors is substrate specific and is sensitive to changes in the polymerization conditions. For N‐(3‐hydroxybutyroyl)‐ϵ‐aminocaproic acid lactone [c(3HB‐ϵAC); 5b ] (IUPAC nomenclature: 2‐methyl‐5‐aza‐1‐oxa‐cycloundecan‐4,11‐dione) bulk and solution polymerizations result in oligomers with an alternating ester amide microstructure. Polymerization of N‐(3‐hydroxypropionyl)‐ϵ‐aminocaproic acid lactone [c(3HP‐ϵAC); 5a ] (IUPAC nomenclature: 5‐aza‐1‐oxa‐cycloundecan‐4‐11‐dione) in dimethylformamide solution and with Bu 2 Sn(OMe) 2 as initiator high molecular weight linear, semi‐crystalline polymers were obtained (T m = 145.9°C). Polymerization of N‐(hydroxypivaloyl)‐ϵ‐aminocaproic acid lactone [c(HPv‐ϵAC); 5c ] (IUPAC nomenclature: 3,3‐dimethyl‐5‐aza‐1‐oxa‐cycloundecan‐4‐11‐dione) in bulk results in amorphous alternating poly(amide‐ester)s with cyclic structure (T g = 6.8°C). The fourteen membered cyclo(diamide‐diester)s 6a‐c (IUPAC nomenclatures:: 4,11‐diaza‐1,8‐dioxa‐cyclotetradecan‐2,5,9,12‐tetraone ( 6a ), 7,14 dimethyl‐4,11‐diaza‐1,8‐dioxa‐cyclotetradecan‐2,5,9,12‐tetraone ( 6b ), 3,10‐dimethyl‐4,11‐diaza‐1,8‐dioxa‐cyclotetradecan‐2,5,9,12‐tetraone ( 6c ) based on β‐hydroxy acids and α‐aminoacids could not be polymerized.