Selectively localized nanosilica particles at the phase interface of PS/PA6/nanosilica composites with co-continuous structure via reactive extrusion

Selectively dispersed functional nanoparticles within one phase or at the phase interface in polymer composites with co-continuous morphology is the most effective way to reduce the percolation threshold of the nano particles. In this study, amino-modified nanosilica particles (mSiO(2)) have been selectively localized at the interface of the PS/PA6/mSiO(2) composites with co-continuous morphology via reactive extrusion. Styrene maleic anhydride (SMA) with different maleic anhydride (MAH) contents is used as compatibilizers. Nanosilica particles can be induced to the interface of PS and PA6 phases by SMA macromolecules through the chemical reaction between the amino groups on nanosilica particle surfaces and MAH groups in SMA macromolecules. The MAH content of SMA macromolecules has large effect on the distribution of nanosilica particles. When nanosilica particles are premixed with SMA2, whose MAH content is 23 wt% and more compatible to PA6 phase, only similar to 26% of the nanosilica particles can be induced to the interface; However, when nanosilica particles are premixed with SMA3, which contains only 8 wt% of MAH and is more compatible to PS phase, nearly 95% of the nanosilica particles can be located at the interface. This work creates a new facile approach to prepare polymer composites where nanoparticles are selectively distributed at the phase interface.