title: The Influence of Crown Ether and Alcohol on Unsaturation and Molar Mass of Poly(propylene oxide)s Prepared by Use of Potassium t-Butoxide: Reinvestigation of Chain Transfer Reactions.
abstract: Potassium t-butoxide dissolved in tetrahydrofuran effectively initiates homogeneous polymerization of propylene oxide at room temperature. Unsaturation and molar mass (M n ) of the polymers prepared depend on the presence of additives, such as macrocyclic ligand 18-crown-6 (L) and t-butanol. Application of the ligand alone results in distinct increase of unsaturation and decrease of M n , whereas use of t-BuOH leads to simultaneous decrease of unsaturation and M n . Activation of t-BuOK/t-BuOH system with the ligand causes further decrease of unsaturation, that is, from 12.0 to 3.5 mol % for OK/OH (1/3) and OK/OH/L (1/3/2) systems, respectively. Unexpectedly, M n of the polymers obtained does not practically change (~4800). This result differs from that reported earlier for neat PO polymerization initiated potassium 1-methoxy-2-propoxide/1-methoxy-2-propanol, in which in the presence of the same ligand M n increases to ~12 400 for the same ratio of reagents. The mechanism of studied processes was discussed.
authors.affiliation: Institute of Chemistry, Faculty of Mathematics, Physics and Chemistry, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Zbigniew
authors.identifier: 0000-0002-7874-0231
authors.initials: Z
authors.lastname: Grobelny
authors.affiliation: Institute of Material Science, Faculty of Computer Science and Material Science, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Andrzej
authors.identifier: 0000-0001-6116-9510
authors.initials: A
authors.lastname: Swinarew
authors.affiliation: Institute of Material Science, Faculty of Computer Science and Material Science, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Jurek-Suliga
authors.affiliation: Institute of Chemistry, Faculty of Mathematics, Physics and Chemistry, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Kinga
authors.initials: K
authors.lastname: Skrzeczyna
authors.affiliation: Institute of Material Science, Faculty of Computer Science and Material Science, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Gabor
authors.affiliation: Institute of Material Science, Faculty of Computer Science and Material Science, University of Silesia in Katowice, 40-007 Katowice, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Łężniak