Syndiospecific oligomerization and polymerization of norbornene with titanium catalysts

Autor:	Paolo Biagini, Arnaldo Rapallo, Lido Porri, Giovanni Ricci, Gianfranco Guglielmetti, Giuseppe Leone
Jazyk:	angličtina
Rok vydání:	2011
Předmět:	chemistry.chemical_classification Materials science Polymers and Plastics Organic Chemistry chemistry.chemical_element Polymer Carbon-13 NMR Amorphous solid Catalysis chemistry.chemical_compound Polymerization chemistry Polymer chemistry Materials Chemistry Single crystal Norbornene Titanium
Zdroj:	Polymer (Guildford) 52 (2011): 5708–5715. doi:10.1016/j.polymer.2011.10.029 info:cnr-pdr/source/autori:Ricci, G.; Leone, G.; Rapallo, A.; Biagini, A.; Guglielmetti G.; Porri L./titolo:Syndiospecific oligomerization and polymerization of norbornene with titanium catalysts/doi:10.1016%2Fj.polymer.2011.10.029/rivista:Polymer (Guildford)/anno:2011/pagina_da:5708/pagina_a:5715/intervallo_pagine:5708–5715/volume:52
DOI:	10.1016/j.polymer.2011.10.029
Popis:	Norbornene (NB) has been polymerized with TiCl 4 –AlR 2 Cl (R = Et, Me, i Bu) at various NB/TiCl 4 molar ratio. The products obtained at low ratio (from ca. 5 to 12, depending on the mode of catalyst preparation) are a mixture of oligomers, from which it has been possible to isolate a crystalline heptamer having a 2,3- exo -disyndiotactic structure by single crystal X-ray analysis. The products obtained at higher NB/TiCl 4 ratio have a higher molecular weight (up to ca. 5000 for the soluble products) and consist of amorphous and crystalline polymers. The crystalline polymers, characterized by X-ray and 13 C NMR, are a new type of stereoregular polynorbornene (PNB), having a 2,3- exo -disyndiotactic structure. Mechanistic aspects are examined and a precise assignment of some resonances in the 13 C NMR spectrum of vinyl-type PNBs is reported.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::eb95ad0d9f2afdddd67cb4d532a5a507 Zobrazit plný text záznamu