摘要

The thermo-optical behavior of immiscible PS/PC blends filled with silica nanoparticles was studied in order to get some information upon the location of nanoparticles in the polymer blend phases and interface using optical microscopy. The systems were designed taking into account rheological and optical requirements, having droplet-matrix morphology, with particle size in the range of the visible light wavelength. The melt blending procedure helped to set the nanoparticles at specific locations including within the PC minor phase, PS matrix phase and PS/PC interphase, which was confirmed via transmission electron microscopy. The light scattering was measured via the normalized transmitted light intensity over temperature, encompassing the Tg of the two polymers. The PS/PC blends showed an increase in the light scattering as compared to the pure polymers, which is magnified upon increasing the PC content. The addition of the nanosilica forming PS/PC/Nanosilica systems greatly reduces the light scattering, particularly above the Tg of the PS phase. The use of hydrophilic nanosilica does not show any appreciable hysteresis upon comparing data from heating and cooling cycles. This type of silica stays mainly trapped within the PC dispersed phase, little interfering with the light scattering, which happens at the polymer-polymer interface. On the other hand, the use of hydrophobic nanosilica does show a clear hysteresis. The hydrophobic silica located at the PS/PC interphase, interfere with the light scattering intensity at this interface, and can be used to identify its presence. The proposed procedure can help control the mixing process, thus improving the effective action of the nanoparticles in the final properties of polymer systems.

  • 出版日期2016-11