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Synthesis and Characterisation of Metal Isobutylsilsesquioxanes and Their Role as Inorganic–Organic Nanoadditives for Enhancing Polymer Thermal Stability
Author(s) -
Carniato Fabio,
Boccaleri Enrico,
Marchese Leonardo,
Fina Alberto,
Tabuani Daniela,
Camino Giovanni
Publication year - 2007
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600683
Subject(s) - chemistry , polypropylene , thermal stability , dehydrogenation , fourier transform infrared spectroscopy , polymer , nanocomposite , metal , chemical engineering , catalysis , polymer chemistry , raman spectroscopy , charring , organic chemistry , physics , optics , engineering
Metal isobutylsilsesquioxanes (M‐POSS) with Ti IV 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 29 Si{ 1 H} 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)