Abstract: Polycaprolactone (PCL)-based nanocomposites with different contents of SiO2 nanoparticles were prepared by a melt-blending method, and effects of SiO2 content on morphology, rheological behavior, static and dynamic mechanical properties, and biodegradability of PCL/SiO2 nanocomposites were investigated. The results indicated that the fraction of small particles as the second phase tended to increase gradually with an increase of SiO2 content. However, the second phase particles presented a serious aggregation when the SiO2 content exceeded 3 wt %. As the SiO2 content and temperature increased, the PCL/SiO2 nanocomposites showed a decrease in their linear viscoelastic region. The nanocomposites also exhibited a rheological percolation in the range of 7 wt %~9 wt %. When the SiO2 content varied from 0 to 9 wt %, the tensile strength and Young's modulus of the nanocomposites presented an increasing trend at first and then decreased. The nanocomposites achieved the maximum tensile strength and Young's modulus at the SiO2 contents of 3 wt % and 7 wt %, respectively. The degradation rate of the nanocomposites was improved gradually with increasing the SiO2 content, and the degradation occurred from the specimen surface in a layer-etching mode.

Key words: polycaprolactone , silica nanoparticle, morphology, rheological behavior, biodegradability