Transesterification and Reactive Compatibilization of Polycarbonate/Poly(butylene Terephthalate) Blends with Supertoughened Mechanical Properties

With increasing demands for high strength/toughness and lightweight, polymer blends have been greatly promoted due to the combined advantages and improved engineering performance. In the current work, polycarbonate/poly(butylene terephthalate) (PC/PBT) blends were prepared via the melt-compounding. Severe ester exchange reactions, evidenced by yellowing and attenuated ester characteristic peaks, were observed in blends with varying ratios, leading to deteriorated PBT crystallinity. Then, two ester exchange inhibitors were incorporated into PC/PBT blends, which showed an evident inhibition effect of transesterification. Alternatively, ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA-co-GMA) as a reactive compatibilizer was introduced into the PC/PBT blend. After adding the compatibilizer, the phase morphology changed from incompatible domains to elongated, elliptical compatible ones. This resulted in a remarkable enhancement of impact strength from 6.3 to as high as 60.0 KJ/m², attributed to chain extension, interfacial cavitation, and strengthened PC–PBT interactions. The current work proposes remarkable polymer blends with the enhancement of toughness, stiffness, and strength.