Isothermal Crystallization and Melting Behaviors of Nano TiO2-Modified Polypropylene/Polyamide 6 Blends

摘要

Titanium dioxide (TiO2) nanoparticles were functional-ized with toluene-2,4-diisocyanate and then polypropyl-ene/polyamide 6/(PP/PA6) blends containing functional-ized-TiO2 were prepared using a twin screw extruder. Isothermal crystallization and melting behavior of the as-prepared composites were investigated using differential scanning calorimetry and wide-angle X-ray diffraction. Isothermal crystallization analysis shows that the TiO2 nanoparticles have two effects on PP/PA6 blends, i.e., it can favor the improvement of crystallization ability and decrease the crystallization rate of PP/ PA6 blends. The improvement of crystallization ability is superior over decreasement of crystallization rate of PA6 chains caused by TiO2, therefore PA6 in PP/PA6/ TiO2 nanocomposites have higher crystallization rate than that of PA6 in pure PP/PA6 blends, which indicated TiO2 nanoparticles favored the crystallization of PA6. The TiO2 nanoparticles show no effects on the equilibrium melting temperature (T^) values of PP phase but decreases the TJJ, values of PA6 phase. In addition, the TiO2 nanoparticles did not change the crystalline polymorph of PP/PA6 blends basically; however, favored the formation of β-PP.