ISSN:
1612-1112
Schlagwort(e):
Gas chromatography
;
Bonded silicas
;
Phase transitions
;
Differential scanning calorimetry
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Summary In order to give a molecular interpretation to the phase transition observed with densely bonded octadecyl-silicas in reversed phase liquid chromatography (RPLC) as well as in gas chromatography (GC), nine new bonded silicas were prepared including grafts with polar groups at the extremities of long spacers (18 carbon atoms). The interpretation is simplified by using large-pore macroporous substrates and inverse GC in conjunction with differential scanning calorimetry (DSC) as the test method. A phase transition is observed in almost all cases, but the temperature range is lower and more extended in comparison to the dimethyloctadecyl reference silica. An interpretation of the phase transition is given, based on the folding of the chains and the resulting “autodensification” of the layer.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02272138
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