ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract A crystalline mesophase state in which molecules show conformational mobility is discussed for cyclododecane and octamethyltetrasiloxane.13C and29Si solid state NMR spectra show changes of the resonance signals which can be explained by changes of the conformation. The transition temperatures in the NMR spectra are correlated with the thermal transitions detected by DSC. Comparisons with the solution spectra give evidence that in case of octamethyltetrasiloxane, the conformational mobility is determined mainly by the molecular packing in the crystal, while packing effects are neglegibly small for cyclododecane. The data are discussed with concern to the corresponding linear chain molecules, i. e. poly(ethylene) and poly(dimethylsiloxane).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00958664
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