Enhanced interlayer strength in 3D printed poly (ether ether ketone) parts

3D printed poly (ether ether ketone) (PEEK) parts have attracted considerable attention in the automotive, medical, and aerospace fields in the past two decades. However, the major obstacle to its further application is weak interlayer strength and severe mechanical anisotropy. Herein, amorphous poly (aryl ether ketone) (aPAEK) was designed as an interlayer reinforcement modifier to strengthen the interlayer strength and reduce mechanical anisotropy of 3D printed PEEK parts. By introducing 7 wt% aPAEK in PEEK filaments, the interlayer strength in 3D printed parts increased 130% from pristine PEEK to aPAEK/PEEK blends. The mechanical anisotropy in the XY plane was reduced to 1.1%, and its X-axis and Y-axis tensile strength still reached 89.2 +/- 3.3 MPa and 88.1 +/- 4.1 MPa, respectively. We demonstrate that these performance enhancements were due to the diffusion and entanglement of aPAEK between the layers. These remarkable results significantly improve the comprehensive mechanical properties of 3D printed PEEK parts, and expand its high-performance applications. This work also yields new insight into the development strategy of additive manufacturing materials by blending.