Konstitutionsisomerie in Polykondensaten. Teil VI. Synthese und Eigenschaften von völlig geordneten und ungeordneten Bipolyamiden aus cis-2,6-Dimethylpiperazin und 1,2,5-Thiadiazol-3,4-dicarbonyl-dichlorid
✍ Scribed by Andreas Mühlebach; Piero Pino
- Book ID
- 102858262
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- German
- Weight
- 1012 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Constitutional Isomerism in Polycondensates. Synthesis and Properties of Perfectly Regular and Random
Bipolyamides from cis-2,6-Dimethylpiperazine and 1,2,5-Thiadiazole-3,4-dicarbonyl Dichloride
The synthesis of constitutionally perfectly regular and random alternating copolyamides from the 'symmetric' monomer 1,2,5-thiadiazol-3,4-dicarbonyl dichloride (4) and the 'non-symmetric' monomer cis-2,6-dimethylpiperazine (7) by solution and interfacial polycondensation methods is described. Their constitutional regularities (s values) were determined by high-resolution I3C-NMR spectroscopy in CDCI, solutions. Ordered and random copolyamides were amorphous with Tg values of ca. 200". However, the regular head/tail and the random copolyamides with low molecular weights could be partially crystallized by annealing and showed large differences in their melting points (549. Beside other physical properties, the membrane properties of the copolyamides were carefully investigated. In H,O desalination by reverse osmosis, no differences in salt rejections and permeabilities between constitutionally regular and random copolyamides were found (within experimental errors). In contrast, the regular head/head/tail/tail-and head/tail-type copolyamides showed considerably larger separation factors in the gas separation (methane/hydrogen) than the random ones.