Organic-inorganic hybrid materials based on N=C=O functionalised silan modified with titanium and zirconium

摘要

This work investigates the influence of the precursor trimethylsilil isocyanate on the sol-gel synthesis of hybrid materials.The obtained Si-O-C-N network is additionally modified by titanium and zirconium alcoxypropoxides in the range of 10 to 30 wt.%.The structure of the obtained hybrid materials before and after pyrolysis up to 1100 degree was investigated by methods of XRD,FTIR and 29Si MAS NMR.We established that the hybrid structure was stable up to 600 degree based on IR study.The structural transformation of the hybrid materials into oxycarbonitrogen system started at 800 degree.The network of the hybrids modified by titanium remained stable and amorphous up to the final temperature of the pyrolysis(1100 degree)compared to the gels modified by more than 10 wt. %Zr.It was confirmed by XRD analysis that the last mentioned are nanocomposite materials,built from carbooxynitrogen vitreous matrix and ZrO_2- nanocrystals(tetragonal).The NMR method verified the presence of heterometallic bonds(Si- O-Ti and Si-O-Zr)and Q_4,ZrQ_3 or TiQ_3,NSiO_3 and D structural units in the gels.