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Study of oligo(aryl ether ketone)s as models for aromatic polyketones
Author(s) -
Rueda Daniel R.,
Zolotukhin Mikhail G.,
Nequlqueo Gloria,
García Carolina,
de la Campa Jose G.,
de Abajo Javier
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(20000201)201:4<427::aid-macp427>3.0.co;2-8
Subject(s) - ether , phenylene , polymer chemistry , chemistry , aryl , lamellar structure , crystallography , isophthalic acid , ketone , crystal structure , diphenyl ether , polymer , organic chemistry , polyester , terephthalic acid , alkyl
The thermal properties and crystal chain packing found for two series (m and p) of oligomeric compounds, with n = 5, 7, 9, and 11 phenylene units, as model compounds for aromatic polyketones are reported. While oligomers of series p contain 1–4 substituted phenylene units those of series m contain an isophthalic group (1–3 substituted phenylene) as the central aryl unit. The keto/ether mole ratio ranges from 0.5 to 0.75. It is confirmed that melting temperatures are clearly dependent on the keto/ether mole ratio as well as on the presence of the isomer defect (isophthalic ring). The keto/ether mole ratio also influences the molecar cross‐section and the fusion enthalpy of crystals. Analysis of X‐ray diffractograms of the powder samples reveals the presence of lamellar crystals with a thickness corresponding to the length of the linear extended molecular conformation ( c axis). Molecular compounds of series p crystallize in the more stable crystal polymorph (form I), observed for aromatic polyketones, while oligomers of series m show polymorphism depending on their chain length. A partial “polymeric” character of the longest compounds ( n = 11) of the two m and p series was found. Nevertheless, their inclusion in this structural study seems to be pertinent.