Structure Development in Reactive Polycarbonate‐Poly(Ethylene Terephthalate) Melt Blends

A series of 50:50 polycarbonate‐poly(ethylene terephthalate) (PC‐PET) blends were formed via reactive melt blending in a torque rheometer at 270°C. The degree of interfacial transesterification between the two homopolymers was promoted by the incorporation of an alkyl titanium catalyst during melt blending. The resultant materials were characterized using differential scanning calorimetry (DSC), small‐angle light scattering (SALS), Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Multicycle DSC showed the uncatalyzed (0 T) blend to exhibit significant reactivity after four consecutive heat‐cool‐heat cycles between 50 and 280°C. The effect of interfacial transesterification on the melt morphology of the 0 T blend was studied using SALS. As transesterification proceeded, the domain size within the blend melt was observed to drop from ∼50 μm to ∼35 μm over a period of 120 s. The range of domain sizes measured by SALS after 120 s s...