New Sn(IV) and Ti(IV) bis(trimethylsilyl)amides in d,l-lactide polymerization, SEM characterization of polymers
| Autor: | Andrei V. Grafov, Marianna Kemell, Sirpa Vuorinen, Timo Repo, Martin Nieger, Markku Leskelä |
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| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
Lactide Polymers and Plastics Trimethylsilyl Organic Chemistry General Physics and Astronomy chemistry.chemical_element Solution polymerization 02 engineering and technology Polymer Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Ring-opening polymerization 0104 chemical sciences chemistry.chemical_compound chemistry Polymerization Polymer chemistry Materials Chemistry 0210 nano-technology Tin |
| Zdroj: | European Polymer Journal. 44:3797-3805 |
| ISSN: | 0014-3057 |
| DOI: | 10.1016/j.eurpolymj.2008.08.006 |
| Popis: | Ring-opening polymerization of d , l -lactide initiated with new chlorotris(bis(trimethylsilyl) amido) tin(IV), tetrakis(bis(trimethylsilyl)amido) tin(IV) and titanium(IV) was investigated. New complexes reveal practically quantitative conversion degrees and produced polymers with higher molecular weight with respect to reference alkoxo-species. The X-ray crystal structure of chlorotris(bis(trimethylsilyl)amido) tin (IV) was investigated. Axial enantiomerism of [SnCl{N(SiMe3)2}3] molecules in solution was studied by high-field dynamic NMR, the value of Gibbs activation energy ΔG‡ = 59.5 kJ/mol. Field emission SEM investigation of bulk polymer samples and thin films on conductive Al foil revealed a stratified fibrous textures in the bulk polymers, as well as nanoscaled topographical features due to coils and entanglements of individual macromolecules in thin films. |
| Databáze: | OpenAIRE |
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