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Mesophasic properties of low molecular weight analogues of nematogenic polycarbonates

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Abstract

The mesophasic behaviour of the following compounds has been investigated by DSC, X-ray diffraction and optical microscopy methods: CH3(CH2)4-CO-R-A n -R-CO-(CH2)4-CH3,n=9→ 14, 16 CH3(CH2)4-CO-R-B n -R-CO-(CH2)4-CH3,n=2, 3A n=-CO-O-(CH2)n−4-O-CO-,B n =-CO-(OCH2CH2) n -O-CO-,R=-O-Ø-C(CH3)=N-N=(CH3)C-Ø-O-,Ø=-C6H4

They have been assumed to be low molecular weight models of homologous nematogenic polymers.

All the examined compounds exhibit nematic mesomorphism. On complete analogy with the corresponding polymers, the thermodynamic data relative to the nematic-isotropic phase transition show a very reduced, if any, odd-even fluctuation. These data are compared with those obtained for very similar compounds, both polymeric and non-polymeric, containing ester linkages between the rigid and flexible groups, to provide evidence of the reliability of the dimeric compounds as models of the polymeric homologues.

Zusammenfassung

Das mesophasische Verhalten der folgenden Verbindungen wurde mittels DSC, Röntgendiffraktion und optischer Mikroskopie untersucht: CH3(CH2)4-CO-R-A n -R-CO-(CH2)4-CH3;n=9→14, 16 CH3(CH2)4-CO-R-B n -R-CO-(CH2)4-CH3;n=2, 3A n =-CO-O-(CH2)n-4-O-CO-;B n =-CO-(OCH2CH2)n-O-CO-;R=-O-C6H4-C(CH3)=N-N=(CH3)C-C6H4-O-. Die Verbindungen wurden als Modelle homologer nematogener Polymere mit niedrigem Molekulargewicht angesehen. Alle untersuchten Verbindungen zeigen einen nematischen Mesomorphismus. Analog zu den entsprechenden Polymeren zeigen die sich auf den nematisch-isotropen Phasenübergang beziehenden thermodynamischen Daten eine, wenn überhaupt, sehr reduzierte ungerade-gerade Fluktuation. Diese Daten werden mit denen verglichen, die für sehr ähnliche, sowohl polymère als auch nicht-polymere Verbindungen mit Esterbindungen zwischen den starren und flexiblen Gruppen erhalten wurden, um Beweise für die Zuverlässigkeit der auf dimeren Verbindungen aufbauenden Modelle für polymère Homologe zu erhalten.

Резюме

Методами ДСК, рентген офазового анализа и оптической микроско пии исследовано мезофазное поведени е соединений со следу ющей структурой: CH3(CH2)4-CO-R-A n -R-CO-(CH2)4-CH3 n=9→14,16 CH3(CH2)4-CO-R-B n -R-CO-(CH2)4-CH3 n=2, 3A n =-CO-O-(CH2) n−4-O-CO-;B n =-CO-(OCH2CN2) n -O-COR =-O-φ-C(CH3)=N-N=(CH3)C-φ-O- φ=C6H4 Предполагалось, что э ти вещества являются низкомолекулярными модельными соединен иями гомологов жидкокрис таллических полимер ов. Все исследованные соеди нения проявляют жидкокристаллическ ий мезоморфизм. Термодинамические д анные относительно ф азового перехода нематик — из отроп, показывают оче нь пониженную, по аналог ии с соответствующим и полимерами, четную-не четную флуктуацию. Да нные сопоставлены с таков ыми, полученными для подобных полимер ных и не полимерных со единений, содержащих эфирные з венья между жесткими и гибкими гр уппами, для доказател ьства достоверности этих д имерных соединений как моделей полимерн ых гомологов

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References

  1. J. A. Buglione, A. Roviello and A. Sirigu, Mol. Cryst. Liq. Cryst., 106 (1984) 169.

    Google Scholar 

  2. A. Roviello and A. Sirigu, Makromol. Chem., 183 (1982) 895.

    Article  Google Scholar 

  3. A. C. Griffin, G. Sigaud and Do Y. Yoon, Macromolecules, 16 (1983) 875.

    Article  Google Scholar 

  4. A. Blumstein, R. B. Blumstein, E. M. Stickles, M. M. Gauthier and F. Volino, Macromolecules, 17 (1984) 177.

    Article  Google Scholar 

  5. R. Capasso, P. Iannelli, A. Roviello and A. Sirigu, to be published

  6. A. Roviello, S. Santagata and A. Sirigu, Makromol. Chem. Rapid Commun., 5 (1984) 209.

    Article  Google Scholar 

  7. A. Roviello and A. Sirigu, Mol. Cryst. Liq. Cryst., 35 (1976) 155.

    Google Scholar 

Download references

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Authors and Affiliations

  1. Dipartimento di Chimica, Università di Napoli, Via Mezzocannone, 4-80134, Napoli, Italy

    C. Carfagna, P. Iannelli, A. Roviello & A. Sirigu

Authors
  1. C. Carfagna
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  2. P. Iannelli
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  3. A. Roviello
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  4. A. Sirigu
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The financial assistance of the Ministero Pubblica Istruzione is acknowledged.

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Carfagna, C., Iannelli, P., Roviello, A. et al. Mesophasic properties of low molecular weight analogues of nematogenic polycarbonates. Journal of Thermal Analysis 30, 1317–1324 (1985). https://doi.org/10.1007/BF01914301

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