Development of poly-(ethylene terephthalate) masterbatches incorporating highly dispersed TiO_2 nanoparticles: Investigation of morphologies by optical and rheological procedures

摘要

Twin-screw melt extrusion was applied to disperse nanoscaled titania particles (TiO_2) into poly(ethylene-terephthalate) (PET) for masterbatch (MB) development. Optical and rheological methods were applied to characterize the particle dispersions within the composite. Our studies show that highest impact on dispersion quality was obtained by the introduction of polymeric dispersing agents, whereas parameters such as screw rotation speed or adapted temperature profiles had only secondary influences. The dispersing agent forms highly dispersed polymer intercalated TiO_2 nanoscaled particle morphologies, whereas for pure PET/TiO_2 dense and considerable amounts of micron scaled TiO_2 aggregates are found. These results are underpinned by scanning transmission electron microscopy (STEM) and by differential scanning calorimetry (DSC) data showing low polymer- particle interaction for pure PET/TiO_2 systems and opposite properties for dispersing agent containing nanocomposites. It is shown that both optical as well as rheological analyses result in consistent and accurate informations on dispersion within the polymer.