Highly reinforcing effect of polycarbonate/poly(ethylene terephthalate) blends by formation of orientation microfibrillar structure

Abstract Highly oriented microfibrillar polycarbonate/poly(ethylene terephthalate) (PC/PET) blends were prepared. Before orientation, the molecular chains of the blends were mostly randomly arranged with a low crystallinity, and low mechanical properties were obtained. Under stress, it was difficult for molecular chains of the amorphous PC phase in blends to form an oriented crystalline structure. With increasing draw ratio, the crystallinity and orientation degree of the PET phase increased, forming a dense lamellar structure with reduced crystalline and amorphous layer thickness, while with increasing PET content the crystalline orientation degree of the PET phase increased with larger sized lamellae. Moreover, the cross‐section of the oriented sample showed an obvious ordered microfibrillar bundle structure, which arranged compactly and orderly along the drawing direction. The tensile strength and modulus of the oriented PC/20 wt% PET sample were up to 126.01 and 7170.10 MPa, which were 66.48% and 317.49% respectively higher than those of pure PC. Therefore, the stress‐induced oriented microfibrillar structure of the PET phase exhibited a highly reinforcing effect on the PC phase and the blend. © 2021 Society of Industrial Chemistry.