Details

Autor(en) / Beteiligte

• BALOGH, L
• FABIAN, L
• MAJOROS, I
• KELEN, T

Titel

Direct monitoring of cationic polymerization by temperature, conductivity and permittivity measurements

Ist Teil von

• Polymer bulletin (Berlin, Germany), 1990, Vol.23 (1), p.75-82

Ort / Verlag

Heidelberg: Springer

Erscheinungsjahr

1990

Quelle

SpringerLINK Contemporary (Konsortium Baden-Württemberg)

Beschreibungen/Notizen

• Direct monitoring of cationic polymerization was accomplished by simultaneous measurement of the average dielectric canstant, representing the dipoles, of the conductivity, produced by unpaired ions, and of the temperature, characteristic for reaction rate. The ionogenic equilibria during the living polymerization of isobutylene by 1,3,5-tris(2-methoxy-2-propyl)benzene/BCl sub 3 in CH sub 2 Cl sub 2 at --25 deg C were demonstrated. Temperature, resistance and capacitance were measured directly in reaction mixture by a specially designed instrument. Both the conductivity and the average dielectric constant change characteristically during the living polymerization, indicating the presence and simultaneous change of unpaired ions and strongly polarized species. The differences between the AMI, and the aging technique were demonstrated and explained. In the latter case slow initiation was observed due to the methoxy--chlorine exchange caused by a reaction with BCl sub 3 . The applied direct monitoring methods helps to understand the role of polarized and ionic species in polymerizations and related processes. Graphs. 20 ref.--AA