3D printing of MOF reinforced flame-retardant PA12 composites with customizable structures†

Polyamide 12 (PA12) requires lightweight, custom moulding and excellent flame retardancy properties for a wide range of aerospace applications. Based on the idea of 3D printed polymer flame-retardant composites with both flame-retardant performance and dimensional accuracy, we demonstrate the successful synthesis of SLS printed 3D advanced flame-retardant composites reinforced by fibrous SiC whiskers modified with polyvinylpyrrolidone uniformly distributed on the surface of MOFs (PVP–SiC–MOFs) by an electrostatic self-assembly process. The PVP–SiC–MOF (HKUST-1)/PA12 powder was prepared by a solution mixing-ultrasonication method, and SLS printing led to porous structured PVP–SiC–HK/PA12 (PPSiHK) composites with high printing precision and integrated mechanical and flame retardant properties. It was shown that the maximum sintering window of PVP–SiC–HK/PA12 was increased by 5 °C. The tensile strength and elongation at break of the composites increased by 6.9% and 20%, respectively, benchmarked against those of printed plain PA12. The pHRR of the PA12 composites decreased by 12.7%, COPR by 44%, and AEHC by 21.5%. This work provides a new idea for the development of 3D-printed polymer flame retardant composite components with high printing accuracy and excellent fire resistance properties for critical applications.