The effect of in-situ fibrillated polytetrafluoroethylene on the rheological, mechanical, and foaming properties of polystyrene based nanocomposite foams

Abstract

Polystyrene/polytetrafluoroethylene (PS/PTFE) in-situ fibrillated nanocomposites were prepared by melt blending using a HAAKE torque rheometer, and the effects of different contents of in-situ nanofibrillated PTFE on the properties of PS/PTFE nanocomposites were studied. The results showed that PTFE was in-situ nanofibrillation in the composites, and the toughness, energy storage modulus and complex viscosity of PS/PTFE nanocomposite are all improved. When the content of PTFE was 3 wt%, the elongation at break was the highest, which was three times that of neat PS. What is more, the addition of PTFE significantly improved the cell morphology of PS/PTFE nanocomposite foams by supercritical fluid foaming. The cell structure and morphology of PS/PTFE (3 wt%) nanocomposite foam was the best under 110°C foaming temperature, and the cell diameter and cell density were 3.27 μm and 1.11 × 10¹⁰ cells/cm³, respectively. In addition, the tensile strength of PS/PTFE nanocomposite foams increased from 35.4 MPa of neat PS foam to 39.6 MPa of PS/PTFE (3 wt%) foam.