Solid‐state shear milling method to prepare PA12/boron nitride thermal conductive composite powders and their selective laser sintering 3D‐printing

Abstract

ABSTRACTThe selective laser sintering (SLS) is one of the most important 3D‐printing technologies. However, the challenges in SLS could be in the limited high material cost and single material performance. Development of high‐performance and multifunctional copowders suitable for SLS is of great importance. Here, polyamide 12 (PA12)/boron nitride (BN) thermal conductive copowders suitable for SLS were successfully prepared through solid state shear milling (S3M) technology in combination with cryogenic pulverization technology. The particle size, morphology, grafting reaction between PA12 and BN, rheology behavior, and coalescence behavior of the obtained PA12/BN copowders were carefully investigated. The optimal amount of silica flow additive (0.5 wt %) was determined to achieve the good powder flowability. Under the optimum 3D‐printing conditions, the fabrication of parts with high BN loading could be achieved. When BN content was at 40 wt %, the flexural strength could reach 10.6 MPa and the thermal conductivity could reach 0.55 W/m·k, 77% higher than that of pure PA12. After treated with phenolic epoxy resin, the tensile strength and flexural strength of the printed parts with 40 wt % BN loading could reach 14.2 and 25.6 MPa, which were 130 and 115% higher than those of the untreated 3D‐printed parts, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48766.