The Effect of Functionalized-TiO2 on the Mechanical Properties of PP/PA6/Functionalized-TiO2 Nanocomposites Prepared by Reactive Compatibilization Technology

Polymeric nanocomposites consisting of the thermoplastic blend of PP and PA6 (70/30 by weight) and the varied amount of the TDI-functionalized TiO2 nanoparticles varied from 0 to 7 phr as a compatilizer, were prepared via melt compounding method. The mechanical performances of the prepared nanocomposites are examined on injection-molded specimens in terms of the tensile and flexural tests. The results showed that the mechanical strength of the nanocomposites increases with the content of functionalized-TiO2 and the best result is achieved when its content is 3 phr. However, for TiO2 content to exceed 3 phr, the nanocomposites become increasingly brittle, as indicated by the decrease in both tensile and flexural strength. The enhanced mechanical strength may be attributed to improved compatibilization of PA6 in PP matrix by virtue of functionalized-TiO2. This conclusion is strongly supported by the evidence from the SEM photographs of the fracture of the nanocomposites, where the better dispersion of the PA6 phase in the PP can be clearly observed. In addition, the dispersion of TiO2 in the nanocomposites was also investigated using a TEM. The result of TEM suggests that the functionalized-TiO2 was well dispersed in the nanocomposites in a nanoscale, because the -NCO groups located at the surface of the TiO2 can chemically associate with PA6, thus improving the compatibility between the TiO2 and the PA6.