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J. Svehla, G. Kickelbick, D. Holzinger, T. Schmidt:
"Formation of Polyester Nanocomposites at Elevated Temperatures: Incorporation of TEOS, Silica Sol and Silica Nanoparticles";
Vortrag: 6. Workshop Anorganische Chemie in Österreich (6.WACÖ), Johannes Kepler Universität, Linz; 29.03.2010 - 30.03.2010; in: "Book of Abstracts", (2010), S. V23.

Inorganic-organic nanocomposites are an important new materials class in which the sol-gel process is often applied for the formation of the inorganic moiety. Commonly used polymerization techniques, such as radical polymerization, can be easily combined with the sol-gel process due to its mild reaction conditions and the vast possibilities for tailoring size and morphology of the inorganic moiety. However specific polymer classes, e.g. polyesters, require much higher reaction temperatures (in the case of polyesters between 150 and 250°C) which leads to changes in the sol-gel reaction mechanisms. Therefore different processing technologies have to be applied if sol-gel modified polyesters are targeted.
In this report we reveal a systematic study on the modification of polyester formulations by the incorporation of tetraethylorthosilicate (TEOS) prehydrolysed silica sol and silica nanoparticles. The resulting inorganic-organic hybrid materials showed increased molecular weights and molecular weight distributions compared to neat polyesters. Reactions of residual silanol and/or ethoxy groups of the silica phase with polyester components led furthermore to branching of the polymer chains. Transmission electron microscopy (TEM) revealed a highly dispersed inorganic phase in the organic matrix. Rheologic investigations of neat and hybrid resins showed moreover enhanced viscosities compared to non-modified polyesters.

Projektleitung Guido Kickelbick:
Polyester Nanokomposite durch in situ Sol-Gel Reaktionen