An effective method to synthesize directly a hard composite material containing uniformly dispersed nanogold particles chemically bonded with a stereospecific, crystalline polymer matrix has been developed. Syndiotactic polypropylene was synthesized and functionalized to have a hydroxyl terminal group (sPP(OH)) via a metallocene catalysis with a selective chain transfer. Next, sPPOH was activated to react with ethylene sulfide forming the thiol-terminated polymer, sPP(SH). sPPSH was then chemically bonded to gold nanoparticles (AuNPs) formed in situ via a reduction of HAuCl4. The bonding between thiol and AuNP stabilized the AuNPs and led to the formation of sPP(AuNPs) composite containing uniformly-dispersed AuNPs of a 19-40 nm size without noticeable aggregation. Furthermore, the chemical bonding of AuNPs has afforded sPPAuNPs a thermal degradation temperature (T-D) 49.4 degrees C higher than the pristine sPP or sPP(OH) and 25.7 degrees C higher than sPPSH without any adverse effect on the crystalline temperature and melting temperature. In addition, the characteristic UV-Vis absorption wavelength of sPP(AuNPs) remains the same at various temperatures, thus indicating the independence of optical property on temperature as well as the good thermal stability of the sPP(AuNPs) composite. H-1 NMR, C-13 NMR, FESEM, STEM, XPS, TGA and DSC were used to investigate the molecular structure, morphology and thermal properties of the resulting sPP(AuNPs) nanocomposite. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4400-4407, 2010