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

Abstract

The 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.

Recent Progress on Polymer Materials for Additive Manufacturing

“…This method was used to produce barium titanate/PA11 and boron nitride/PA12 composite powders. [162,195] Solution mixing is a method that utilizes a solvent in which a polymer is soluble and fillers can be dispersed. In this process, a polymer is first dissolved in a suitable solvent, followed by the dispersion of fillers, which is typically aided by ultrasonication or stirring to better mix the filler suspension with the polymer solution.…”

Current advances and future perspectives of additive manufacturing for functional polymeric materials and devices

“…Currently, the major category of commercial raw material for SLS printing is polyamide (PA) 12, which accounts for more than 95% of the market. In response to this problem, Wang et al [38][39][40][41][42][43] have innovatively established and developed advanced technologies, such as organic/inorganic hybridization, solid-phase shear milling, and ultrasonic irradiation, to prepare polymerbased micro-/nanofunctional composite powders suitable for SLS processing such as highly filled PA11-based piezoelectric functional composite powder, [39][40][41] PA12-based conductive/thermal composite powder, 38,42,43 and self-healing silicone rubber elastomer. Besides, they also invented novel spheroidization technology and equipment (Figure 1C-1), which can prepare spherical functional powders with excellent fluidity and high bulk density on a large scale, effectively solving the problem of limited types and the lack of functionality of functional materials for SLS 3D printing technology.…”

“…Currently, the major category of commercial raw material for SLS printing is polyamide (PA) 12, which accounts for more than 95% of the market. In response to this problem, Wang et al 38–43 . have innovatively established and developed advanced technologies, such as organic/inorganic hybridization, solid‐phase shear milling, and ultrasonic irradiation, to prepare polymer‐based micro‐/nanofunctional composite powders suitable for SLS processing such as highly filled PA11‐based piezoelectric functional composite powder, 39–41 PA12‐based conductive/thermal composite powder, 38,42,43 and self‐healing silicone rubber elastomer.…”

Hybrid of multi‐dimensional fillers for thermally enhanced polyamide 12 composites fabricated by selective laser sintering

“…On the one hand, the molding methods of abovementioned thermal conductive polymer composites are mainly based on traditional processing techniques, such as compression molding and injection molding. Although there exist some advantages in traditional processing methods, such as short molding cycle and high production efficiency, 6 it is difficult for traditional processing techniques to realize the manufacture of thermal conductive polymer composite components with complex shape and structure. 7 On the other hand, in order to obtain high thermally conductive polymer composites, high content of thermal conductive fillers is generally required.…”