Assessment of Jet Milling as an Alternative Processing Technique for Preparing Polysulfone Hard Nanocomposites

This work describes how a solid-state blending method such as jet milling can be used to successfully
prepare polysulfone (PSU)/ c-alumina nanocomposites. For comparison purposes, conventional melt
extrusion was used as well. Morphological analysis revealed how jet mill blending allows obtaining
well-dispersed c-alumina nanoparticles within a polysulfone matrix without any surface treatment, with
an important decrease of particle size promoted by the breakup of agglomerates and aggregates due
to the particle-particle impacts during processing, which was not observed in the extruded
nanocomposites. DSC analysis demonstrated that jet-milling processing promoted Tg enhancements
with alumina addition, while TGA experiments confirmed the increment of thermal stability of the
nanocomposites prepared by jet milling when compared with the composites prepared by extrusion.
The tensile tests showed that ductility remains at a high value for milled nanocomposites, which
agreed with the fracture surface images revealing large plastic deformation as a function of the
alumina content. This comparative study indicates that the dispersion of nanoparticles in PSU was
more homogeneous, with smaller nanoparticles when preparing nanocomposites using jet milling,
showing a strong correlation with the enhanced final properties of the nanocomposites. These
results strongly suggest that jet milling can be considered as a more efficient and industrially
scalable route for preparing polymer nanocomposites when compared with techniques that
consider functionalization of nanofillers which is expensive and time consuming.