Preparation of urea-poly(tetrahydrofuran) complexes and their application for fractionation of oligomers
| Autor: | V. Enkelmann, U. Westphal, Gerhard Wegner, M. Dröscher, Gudrun Schmidt |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
chemistry.chemical_classification
Polymers and Plastics Fractionation Polymer Reversed-phase chromatography Oligomer law.invention chemistry.chemical_compound Crystallography Colloid and Surface Chemistry chemistry Osmometer law Polymer chemistry Materials Chemistry Urea Physical and Theoretical Chemistry Crystallization Tetrahydrofuran |
| Zdroj: | Colloid and Polymer Science. 263:120-127 |
| ISSN: | 1435-1536 0303-402X |
| DOI: | 10.1007/bf01412786 |
| Popis: | The synthesis of the urea channel inclusion complexes of poly(tetrahydrofuran)) (PTHF) is described. These complexes could be obtained in the form of single crystals forM n ≤ 1700 g/mol of PTHF as the guest, and they exhibit a hexagonal unit cell (a=8.20(2) A,c=11.05(3) A) very similar to the wellknown urea-n-alkane complexes. X-ray investigations, elemental analysis and density measurements suggest an all trans zig-zag conformation of the polymer chain. The formation of the complexes was exploited for the purpose of fractionation of PTHF, making use of the correlation between temperature of crystallization andM n of the included polyether chain. The distribution and the molecular weights of the fractions, obtained by extractive crystallization, were determined by reversed phase HPLC analysis and vapour pressure osmometry (VPO). Narrow fractions with Mw/Mn=1.02 were obtained from commercial PTHF samples. Successive fractionation was applied also on product mixtures from oligomer synthesis, as demonstrated for the separation of the dodecamer H-(o-(CH2)4-)12OH. |
| Databáze: | OpenAIRE |
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