Controlled synthesis of star-shaped L-lactide polymers using new spirocyclic tin initiators
2002 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 3, no 4, 684-690 p.Article in journal (Refereed) Published
The reaction between pentaerythritol ethoxylate compounds and dibutyltin oxide was developed as a route to synthesize two new spirocyclic tin initiators. The initiators were successfully synthesized and they were characterized by H-1 NMR and differential scanning calorimetry (DSC). The H-1 NMR spectra showed the characteristic signals for the methylene protons in the ether chains. Furthermore, the usefulness of the new initiators was examined in ring-opening polymerizations of L-lactide in chloroform at 60 degreesC. L-Lactide was polymerized at monomer-to-initiator ([M]/[I]) ratios between 20 and 500. The results indicated that the initiation was instantaneous and that the molecular weight distribution was very narrow, <1.13, The number average molecular weight could be controlled by the [M]/[I] ratio, and the yield was very high. H-1 NMR, size exclusion chromatography, and DSC were used to clarify the architecture, The expected results were obtained. The star-shaped polymers had a smaller hydrodynamic volume, and the melting point was lower than that obtained for the corresponding linear poly(L-lactide).
Place, publisher, year, edition, pages
2002. Vol. 3, no 4, 684-690 p.
LIVING CATIONIC-POLYMERIZATION, RING-OPENING POLYMERIZATION, BLOCK-COPOLYMERS, STANNOUS OCTOATE, POLYLACTONES, PENTAERYTHRITOL, POLYSTYRENE, POLY(L-LACTIDE), MECHANISM, ALKOXIDES
IdentifiersURN: urn:nbn:se:kth:diva-13188DOI: 10.1021/bm020009oISI: 000176716700008OAI: oai:DiVA.org:kth-13188DiVA: diva2:321695
QC 201006022010-06-022010-06-022010-06-02Bibliographically approved