Mitkus Rytis, Scharnofske Marlitt, Sinapius Michael
Technische Universität Braunschweig, Institute of Mechanics and Adaptronics, Langer Kamp 6, 38106 Braunschweig, Germany.
Polymers (Basel). 2021 Nov 15;13(22):3948. doi: 10.3390/polym13223948.
Notably, 3D printing techniques such as digital light processing (DLP) have the potential for the cost-effective and flexible production of polymer-based piezoelectric composites. To improve their properties, conductive nanomaterials can be added to the photopolymer to increase their dielectric properties. In this study, the microstructure, viscosity, cure depth, and dielectric properties of ultraviolet (UV) light curable 0.1 wt.% nanomaterial/photopolymer composites are investigated. The composites with multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and carbon black (CB) are pre-dispersed in different solvents (acetone, isopropyl alcohol, and ethanol) before adding photopolymer and continuing dispersion. For all prepared suspensions, a reduction in viscosity is observed, which is favorable for 3D printing. In contrast, the addition of 0.1 wt.% nanomaterials, even with poor dispersion, leads to curing depth reduction up to 90% compared to pristine photopolymer, where the nanomaterial dispersion is identified as a contributing factor. The formulation of MWCNTs dispersed in ethanol is found to be the most promising for increasing the dielectric properties. The post-curing of all composites leads to charge immobility, resulting in decreased relative permittivity.
值得注意的是，诸如数字光处理（DLP）之类的3D打印技术具有以经济高效且灵活的方式生产聚合物基压电复合材料的潜力。为了改善其性能，可以将导电纳米材料添加到光聚合物中以提高其介电性能。在本研究中，对紫外线（UV）光固化的0.1 wt.%纳米材料/光聚合物复合材料的微观结构、粘度、固化深度和介电性能进行了研究。含有多壁碳纳米管（MWCNT）、石墨烯纳米片（GNP）和炭黑（CB）的复合材料在添加光聚合物并继续分散之前，先在不同溶剂（丙酮、异丙醇和乙醇）中预分散。对于所有制备的悬浮液，均观察到粘度降低，这有利于3D打印。相比之下，添加0.1 wt.%的纳米材料，即使分散性较差，与原始光聚合物相比，也会导致固化深度降低高达90%，其中纳米材料的分散被认为是一个影响因素。发现分散在乙醇中的MWCNT配方在提高介电性能方面最具前景。所有复合材料的后固化都会导致电荷固定，从而导致相对介电常数降低。
