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On the difference of reactivities of various aggregated forms of aluminium triisopropoxide in initiating ring‐opening polymerizations
Author(s) -
Duda Andrzej,
Penczek Stanislaw
Publication year - 1995
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1995.030160112
Subject(s) - polymerization , trimer , reactivity (psychology) , polymer chemistry , monomer , tetramer , chemistry , aluminium , ring opening polymerization , bulk polymerization , dimer , organic chemistry , polymer , radical polymerization , medicine , alternative medicine , pathology , enzyme
The polymerization of ε‐caprolactone (εCL) initiated with aluminium triisopropoxide (Al(O i Pr) 3 ) trimer ( A 3 ) and/or tetramer ( A 4 ) was studied. The rate of A 3 ⇔ A 4 interconversions in the diluted (≤0,1 mol · L ‐1 ) C 6 D 6 , C 6 D 6 /εCL, and THF/εCL solutions were found to be slow, when compared with the rate of propagation. Comparison of the 1 H NMR spectra of the initiators with those of the polymerization mixtures revealed that A 3 is much more reactive than A 4 in their reactions with εCL. From the initiator reacted with εCL all threeO i Pr groups from Al(O i Pr) 3 are transferred into the poly(εCL) as end groups. Kinetic studies of polymerization confirmed the large reactivity difference between A 3 and A 4 .