填充密度调控3D打印h-BN/TPU复合材料热力学性能研究

Research on Thermo-Mechanical Properties of 3D Printed h-BN/TPU Composites with Filling Density Regulation

摘要: 为探究填充密度对FDM 3D打印h-BN/TPU导热聚合物复合材料热力学性能的调控规律，以20 wt%填料含量下的h-BN/TPU为研究体系，设置80%、90%、100%三组填充密度开展单因素实验，结合SEM、激光导热仪、热重分析仪与万能材料试验机表征材料微观结构与宏观性能。结果表明：填充密度从80%提升至100%，熔丝界面融合更紧密、内部孔隙率明显降低，h-BN片层沿水平方向取向程度提高；复合材料热导率、700℃残炭率、拉伸强度与断裂伸长率均呈上升趋势，实现导热性能、热稳定性与力学性能协同增强。研究明确填充密度通过调控熔丝粘合形貌与填料取向影响材料性能，为3D打印导热复合材料工艺优化提供实验依据。

Abstract: In order to explore the regulation of filling density on the thermodynamic properties of FDM 3D printed h-BN/TPU thermal conductive polymer composites, a single factor experiment was carried out to h-BN/TPU with filler mass fraction of 20 wt% and three groups of filling densities of 80%, 90% and 100%. The microstructure and macro properties of the composites were characterized by SEM, laser thermal conductivity analyzer, thermogravimetric analyzer and universal material testing machine. The results show that the filling density increases from 80% to 100%, the fusion interface is closer, the internal porosity is significantly reduced, and the horizontal orientation of h-BN layer is improved; The thermal conductivity, 700˚C residual carbon rate, tensile strength and elongation at break of the composite showed an upward trend, achieving the synergistic enhancement of thermal conductivity, thermal stability and mechanical properties. The results show that the filling density affects the material properties by adjusting the fuse bonding morphology and filler orientation, which provides an experimental basis for the process optimization of 3D printing thermal conductive composites.