Fine dispersion morphology of polystyrene/poly(ethylene terephthalate glycol) blending generation for controlled foaming behavior

Abstract

Polystyrene/poly(ethylene terephthalate glycol) (PS/PETG) blends with different PETG contents were prepared using a Haake internal mixer at 190 °C. Morphologies of the PS/PETG blends exhibited a sea-island structure with homogeneity and a fine degree of dispersion. Additionally, it was found that the size of spherical PETG particles in a PS matrix maintained an unchanged scale but the density of dispersed particles increased with a PETG content from 10 wt% to 25 wt%. The dispersion density or interface density could be tuned by the added PETG content. Furthermore, the rheological properties and melt strength of PS and PS/PETG blends were also tested and discussed. The addition of PETG in a PS matrix makes little difference in the PS/PETG blends. Finally, foaming behaviors of the PS and PS/PETG blends were investigated and the mechanism of these blends foaming was analyzed. We concluded that addition of the PETG phase not only facilitated foaming nucleation but also increased the CO₂ in solution for all the blends during the foaming process. This resulted in foam with a higher expansion ratio and better uniform cell structure in comparison with PS. However, PETG addition contents should be controlled to a certain degree, or a serious open-cell phenomenon will occur.