Polymers of carbonic acid, 4. Crystalline smectic polyurethanes derived from piperazine or 4,4′‐bipiperidine and diphenols containing aliphatic spacers
Abstract 4,4′‐Alkylenedioxydiphenols ( 3a–e ), prepared from α,ω‐dibromoalkanes and hydroquinone, were converted with phosgen to the corresponding dichloroformates 4a–e , which were reacted with piperazine, trans ‐2,5‐dimethylpiperazine or 4,4′‐bipiperidine under the conditions of interfacial conden...
| Published in: | Die Makromolekulare Chemie |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1989
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1002/macp.1989.021901023 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fmacp.1989.021901023 https://onlinelibrary.wiley.com/doi/pdf/10.1002/macp.1989.021901023 |
| Summary: | Abstract 4,4′‐Alkylenedioxydiphenols ( 3a–e ), prepared from α,ω‐dibromoalkanes and hydroquinone, were converted with phosgen to the corresponding dichloroformates 4a–e , which were reacted with piperazine, trans ‐2,5‐dimethylpiperazine or 4,4′‐bipiperidine under the conditions of interfacial condensation. The DSC measurements of polyurethanes derived from 2,5‐dimethylpiperazine displayed one endotherm indicating a normal melting process, whereas the polyurethanes derived from piperazine or 4,4′‐bipiperidine showed a reversible first order phase transition below the melting point. WAXS powder patterns indicate a change between two different smectic modifications. Thermomechanical analyses (penetration method) proved that also the high‐temperature smectic modification is a solid state and not a liquid‐crystalline one. |
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