热塑性聚氨酯吸波复合材料的3D打印研究

Research on 3D Printing of Thermoplastic Polyurethane Absorbing Composites

为制备可供3D打印的具有吸波功能的复合丝材,以热塑性聚氨酯(TPU)作为基体材料,以羰基铁粉(CIP)与多壁碳纳米管(MWCNTs)为吸波剂,采用熔融共混法制备TPU/MWCNTs-CIP复合材料。研究CIP添加量对TPU/MWCNTs-CIP复合材料力学性能和流动性能的影响,并分析复合材料的挤出拉丝性能和熔融沉积成型(FDM)打印能力。结果表明:CIP质量分数为60%时,TPU/MWCNTs-CIP复合材料具有较好的力学性能,可制备符合FDM工艺要求的丝材。将制备的复合丝材经过FDM打印成型得到蜂窝吸波结构,采用弓形法对其进行电磁波反射率测试,蜂窝结构仅在3 mm的厚度下达到最低吸波反射损耗值(-33.8 dB)。

In order to develop a composite filament with wave absorbing function for 3D printing, thermoplastic polyurethane(TPU) was used as the matrix material, carbonyl iron powder(CIP) and multi-walled carbon nanotubes(MWCNTs) were used as wave absorbers, and the TPU/MWCNTs-CIP composites were prepared by melt blending method. The effects of CIP addition on the mechanical properties and flow properties of TPU/MWCNTs-CIP composites were investigated, and the extrusion wire drawing properties and fused deposition modeling(FDM) printing capabilities of the composites were analyzed. The results show that when the mass fraction of CIP is 60%, the TPU/MWCNTs-CIP composite has good mechanical properties and can be prepared into a wire that meets the requirements of the FDM process. The composite wire was printed and formed by FDM to obtain the honeycomb absorbing structure. The electromagnetic wave reflectivity test was carried out by the bow method. The honeycomb structure can reach the lowest absorbing reflection loss value(-33.8 dB) only under the thickness of 3 mm.