Abstract
Metal isobutylsilsesquioxanes (M-POSS) with TiIV and V V metal centres have been prepared by direct corner-capping of trisilanolisobutyl-POSS (1). The synthetic procedure has been followed in solution by FTIR spectroscopy and samples have been characterised by 29Si{1H} NMR, FTIR, FT-Raman and UV/Vis spectroscopy in order to study the structure and the chemical properties of the transition metal centres incorporated in the synthesised compounds. The corner-capping reaction basically lead to tetrahedrally coordinated metal centres inserted in the siliceous cage. The hybrid inorganic-organic nature of these compounds and the possibility of dispersing catalytically active metal centres in a highly efficient way within organic matrices have been investigated by dispersing the title compounds at 3 wt.-% in a polypropylene matrix by melt blending, which leads to nanocomposite materials. A study of the thermal degradation of polypropylene, trisilanolisobutyl-POSS and metal-isobutyl-POSS composites shows a significantly enhanced thermal stability under oxidative conditions only when metal-containing silsequioxanes are dispersed, along with an extended formation of condensed polyaromatic compounds (charring products). This evidence is consistent with a possible catalytic effect favouring oxidative dehydrogenation of the polymeric organic chains occurring in the condensed phase under combustion conditions, and highlights a possible promising use of M-POSS as fire-retardant additives for polymers.
Lingua originale | Inglese |
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pagine (da-a) | 585-591 |
Numero di pagine | 7 |
Rivista | European Journal of Inorganic Chemistry |
Numero di pubblicazione | 4 |
DOI | |
Stato di pubblicazione | Pubblicato - 2007 |