Research: 3D printed structures inspired by shell nacre with outstanding mechanical and flame retardant properties

As fire, military, industrial and
aviation
aerospace
The need for high performance thermal insulation in engineering, lightweight and strong flame retardant structures has been extensively studied. In addition, the miniaturization of electronic devices and the problem of heat accumulation in multi-functional integration have increased the demand for thermal control structures in electronic devices.
ceramics
and polymers are ideal for thermal control/flame retardant structures due to their good processability and excellent mechanical, thermal and electrical properties. However, the defect resistance and high strength properties of these two materials are not well combined.There is a way in nature to combine ceramic sheets with
biology
The polymer interlayers are assembled together to create a strong and flaw-resistant structure. Evolved over millions of years, nacre has exceptional strength, stiffness and toughness.

In view of this, the team of Assistant Professor Yang Yang of San Diego State University, the team of Professor Yong Chen of the University of Southern California, and the team of Professor Ziyu Wang of Wuhan University have cooperated to develop a nacre-inspired 3D printing structure, which has excellent mechanical and Flame retardant properties. Related research was published in an article entitled “3D Printing of Nacre inspired Structures with Exceptional Mechanical and Flame-retardant Properties” in the journal Research (a Science Partner Journal). The participants were Assistant Professor Xiangjia Li of Arizona State University, Assistant Professor Wenwu Xu of San Diego State University, Assistant Professor Qiming Wang of University of Southern California, PhD student Qingqing He of San Diego State University, PhD student Yushun Zeng, Gengxi Lu of USC, and postdoctoral fellow Laiming Jiang, Master students Siqi Xiao, Shuang Lin, etc.

Article Highlights

1. We report a rotation-blade casting-assisted 3D printing process to build nacre-inspired, highly loaded boron nitride (BN) BN arrangements into arbitrarily complex structures with Enhanced mechanical properties, highly anisotropic thermal conductivity and excellent flame retardancy.

2. The orientation mechanism of boron nitride (BN) in high viscosity slurry was studied. The nacre-inspired 3D printed structure with high loading of a-BN (55 wt%) showed higher fracture toughness and specific strength than natural nacre. Fundamental mechanistic studies revealed that the excellent mechanical properties were attributed to crack deflection, bridging of a-BNs, and covalent bonding between TMSPMA and the polymer matrix enhanced by large shear forces during boron nitride pull-out. Compared with pure photocurable resin, the structure enhances anisotropic thermal conductivity by a factor of 5.8.

3. The mechanical and flame retardancy enhancement mechanisms are analyzed, and it is further demonstrated that the 3D printed heat sink with branched structure shows effective thermal control and heat dissipation for high-power light-emitting diodes (LEDs).

4. 3D printed helmets and armors have been shown to have both flame retardant and mechanical protection properties, demonstrating potential applications in military, firefighting equipment, machinery, and aerospace engineering.

(responsible editor: admin)