Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich.
mehr Informationen...
In situ X-ray diffraction performed on mesophase formation during the carbonization of acenaphtylene
Ist Teil von
Carbon (New York), 1985, Vol.23 (3), p.273-280
Ort / Verlag
Oxford: Elsevier Ltd
Erscheinungsjahr
1985
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
The principal steps of mesophase formation which appear during the acenaphtylene carbonization were studied by
in situ X-ray diffraction. Additional information about the process was also obtained by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and infrared spectroscopy.
We observed firstly the melting of acenaphtylene between 90 and 100°C which undergoes a polymerization process from 200°C/230°C to 350°C/380°C. Then cracking of polyacenaphtylene at 400°C leads to a liquid phase containing principally decacyclene molecules. The liquid recrystallizes by cooling in a structure that we have previously identified as the high-temperature crystalline φ
2 phase of decacyclene. In the case of acenaphtylene pyrolysis, the φ
2 phase melting point is depressed due to the other molecular species which constitute the final cracking blending.
At 420°C the liquid pitch turns into a new phase which we call φ
2′ which would have a discotic type structure with a short range order. The high amount of free radicals in the acenaphtylene pitch at such a temperature facilitates the linkage of decacyclene molecules through the φ
2′ phase. This process promotes the formation of polyaromatic layers which leads to the ordering existing in the Brooks and Taylor mesophase spheres.