Compatibility and toughening mechanism of poly(ethylene terephthalate)/polycarbonate blends

Abstract

AbstractPoly(ethylene terephthalate) (PET)/polycarbonate (PC) blends with methyl methacrylate‐styrene‐butadiene copolymer as compatibilizer (CP) were prepared. Compared with pure PET, the notched impact strength of the blend was improved significantly, while high tensile strength and 50%–70% optical transparency could be maintained. In particular, for the PET/70 wt% PC sample the notched impact strength sharply increased by 955% with the addition of compatibilizer. The ΔTg of the two phases of the blends decreased on blending, exhibiting partial compatibility. Below 50 wt% PC, the dispersed PC phase presented uneven dispersion with large aggregates and a clear interface, while above 50 wt% PC a reverse phase transformation occurred and the PET phase was evenly dispersed in the PC matrix with small aggregates and obvious interface transition areas. The introduction of CP promoted spherical PC particles to uniformly disperse in the matrix, and the interface transition area of the two phases became very wide. Moreover, the CP itself ran through the matrix to form a ‘quasi‐network distribution’ and the compatibility was greatly improved, thus leading to an obvious enhancement of the impact toughness of the blend. © 2020 Society of Industrial Chemistry