ma000048x_si_001.pdf (91.38 kB)
Supramolecular Association of Acid-Terminated Poly(dimethylsiloxane)s. 2. Molecular Weight Distributions
journal contribution
posted on 2000-10-04, 00:00 authored by S. Abed, S. Boileau, L. BouteillerAssociation through hydrogen bonding of benzoic acid-terminated poly(dimethylsiloxane)
1 in low-polarity solvents has been studied by FTIR spectroscopy and viscosimetry. At high concentrations,
chain extension leads to high viscosity values, whereas at low concentrations, intramolecular hydrogen
bonding is responsible for the formation of low-viscosity cyclic species. A quantitative model based on
Jacobson−Stockmayer theory and describing the competition between chain extension and macrocyclization is presented. On the basis of this model, the molecular weight distributions of ring and chain fractions
has been calculated as a function of concentration in three different solvents. The length of the siloxane
backbone has been shown to have a large influence on the cyclic weight fraction and on the average
molecular weight.