高分子基石墨烯-碳纳米管复合材料的选区激光烧结及电磁屏蔽特性研究

THE INVESTIGATION OF SELECTIVE LASER SINTERING AND ELECTROMAGNETIC SHIELDING PROPERTIES OF POLYMER_x0002_BASED GRAPHENE-CARBON NANOTUBE COMPOSITE MATERIAL

纪馨竹

11930369

硕士

材料工程

白家鸣

2021

2021年6月21日

南方科技大学

深圳

本文对可应用于选区激光烧结(Selective Laser Sintering，SLS)，具有电磁屏蔽性能的复合材料粉末的制备、表征和加工性能进行了研究。采用相分离法制备了添加碳纳米管(Carbon Nanotubes，CNTs)和石墨烯的含量均为 1 wt.%、3 wt.%、5 wt.%以及 7 wt.%的尼龙 12-碳纳米管/石墨烯的复合材料粉末，成功地获得了导电填料分散均匀，包覆良好的近球形复合材料粉末。通 过 对 制 备 得 到 的 复 合 材 料 粉 末 进 行 一 系 列 表 征 ， 与 纯 尼 龙 12(Polyamide 12，PA12)粉末相比，复合材料粉末的粒径略有下降，形状为近球形，添加的导电填料均匀地包覆在 PA12 粉末表面，CNTs 和石墨烯在 PA12粉末颗粒表面构成了导电通路。复合材料粉末与 PA12 粉末的熔融温度差别不大，但结晶温度要比 PA12 粉末高出约 5 ℃，且复合材料粉末的热稳定性优于 PA12 粉末。对复合材料粉末的加工性能和打印参数进行了探索，通过上述表征实验得到的结果对打印参数进行预设，并通过 14 组实验进一步确定了复合材料粉末的激光功率、扫描速度和分层厚度。选定了最佳的一组加工参数：预热温度设置 180 ℃、扫描间距设置 0.2 mm、激光功率设置 8.4 W、扫描速度设置 60 mm/s、分层厚度设置 0.05 mm。采用上述参数对复合材料粉末进行选区激光烧结打印，并对打印件进行了电磁屏蔽性能的测试。与 PA12 打印件相比，激光烧结过程会使 PA12 粉末由相转变为相。在高分子基体中加入导电填料，使得复合材料制件的电磁屏蔽性能得到了显著提升。当导电填料含量增加到 7 wt.%时，复合材料打印件的电磁屏蔽性能从 0.6 dB 提高到了 12.73 dB。导电填料的加入增强了PA12 打印件的热稳定性，提高了打印件的热学性能。

In this paper, the preparation, characterization and processing properties of Selective Laser Sintering (SLS) based composite powders with electromagnetic shielding properties were investigated. Carbon Nanotubes (CNTs) with conductive filler and Nylon-12-carbon Nanotubes/graphene composite powder containing 1 wt.%、3 wt.%、5 wt.% and 7 wt.% graphene were prepared by phase separation method. The near spherical composite powders with good dispersion of conductive filler were obtained successfully.Through a series of characterization of the composite powder prepared, compared with pure Polyamide 12 (PA12) powder, the particle size of the composite powder decreased slightly, and the shape of the composite powder was nearly spherical. The conductive filler added was uniformly coated on the surfa ce of PA12 powder. CNTs and graphene formed conductive pathways on the surface of PA12 powder particles. The melting temperature of the composite powder and PA12 powder had little difference, but the crystallization temperature was about 5℃ higher than that of PA12 powder, and the thermal stability of the composite powder was better than that of PA12 powder.The processing properties and printing parameters of the composite powder were explored. The printing parameters were preset based on the results of th e above characterization experiments, and the laser power, scanning speed and lamination thickness of the composite powder were further determined through 14 groups of experiments. The best set of processing parameters were selected: preheating temperature 180 ℃, scanning spacing 0.2 mm, laser power 8.4 W, scanning speed 60 mm/s, layer thickness 0.05 mm.The composite powders were printed by selective laser sintering using the above parameters, and the electromagnetic shielding properties of the printed parts were tested. Compared with the PA12 print, the laser sintering process changes the PA12 powder from phase to normal phase.The electromagnetic shielding performance of the composites is improved significantly by adding conductive filler into the polymer matrix. When the content of conductive filler IIAbstractis increased to 7 wt.%, the electromagnetic shielding property of the printed part is improved from 0.6 dB to 12.73 dB. The addition of conductive filler enhances the thermal stability of PA12 printings and improves the thermal properties of the printings.

电磁屏蔽 尼龙 12 选区激光烧结 碳纳米管 石墨烯

electromagnetic shielding nylon 12 select laser sintering carbon nanotubes graphene

中文

独立培养

南方科技大学

纪馨竹. 高分子基石墨烯-碳纳米管复合材料的选区激光烧结及电磁屏蔽特性研究[D]. 深圳. 南方科技大学,2021.