ISSN:
0959-8103
Schlagwort(e):
cyclosilazanes
;
polysilazanes
;
cationic polymerization
;
kinetics
;
methyl triflate
;
adiabatic calorimetric technique
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
The ring-opening polymerization of hexamethylcyclodisilazane (D2NMe), initiated by methyl triflate in 1,2-dichloroethane, forms in the first, fast kinetic step both linear polymer and cyclic dimer (D4NMe). Subsequently a slow depolymerization process occurs leading to exclusively cyclotrisilazane (D3NMe). On the basis of kinetic measurements carried out using an adiabatic calorimetric technique and complementary experiments, mechanisms of both propagation, cyclization and back-biting reactions are proposed. The influence of the reaction temperature was also studied; it is demonstrated that, at low temperature, polymerization does not lead to cyclic oligomer formation. In such conditions, the polymerization presents a ‘living’ character.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pi.1994.210330203
Permalink