A new kind of antioxidant 4‐[(3‐(triethoxysilyl)propylimino)methyl]‐2,6‐di‐tert‐butylphenol consisting of an alkoxysilyl group and a 2,6‐di‐tert‐butylphenol stabilizing moiety was synthesized and tested in isotactic poly(propylene). FT‐IR, 1H‐NMR, 13C‐NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) were used for characterization of synthesized silane stabilizer. The derivative of 4‐[(3‐(triethoxysilyl)propylimino)methyl]‐2,6‐di‐tert‐butylphenol was also prepared by the condensation reaction using the sol‐gel process. Stabilizing activity of the new silane stabilizer and its condensed form was verified by chemiluminiscence and thermogravimetry measurements in oxygen atmosphere and compared with conventional 2,6‐di‐tert‐butyl‐4‐methyl‐ phenol as well as with the conventional stabilizing system based on the mixture of Irganox 1010/Irgafos168 (weight ratio of 1:2). Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]