Ionic liquid-aided liquid phase exfoliation of graphene and improved electric and electromagnetic properties of PLA/EVA/graphene composites

IF 5.9 3区材料科学 Q2 CHEMISTRY, PHYSICAL

FlatChem Pub Date : 2025-06-05 DOI:10.1016/j.flatc.2025.100893

Alessandra de A.P. Gabino , Bluma G. Soares , Elaine F. da Silva

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引用次数: 0

Abstract

The dispersion of carbonaceous fillers in polymeric matrices presents a significant challenge due to the difference in surface energy between fillers and the polymers. In this study, a straightforward and cost-effective method was employed to exfoliate graphene nanoplatelets (GNP) in water using the liquid phase exfoliation (LPE) technique, with ionic liquids (ILs) serving as surfactants. The treated graphene was subsequently incorporated into PLA/EVA (60:40 wt%) composites, which were evaluated for their rheological and alternating current (AC) electrical properties, as well as their electromagnetic absorptivity in the X and Ku Band (8.2 to 18 GHz). Raman spectroscopy confirmed modifications in the GNP structure, indicating successful exfoliation. Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) revealed that a portion of IL adhered to the GNP particles and was thus incorporated into the polymeric composites. The synthesized imidazole sultone-based IL promoted more intense exfoliation and particle fragmentation, leading to a reduction of electrical conductivity and electromagnetic absorptivity of the composite. In contrast, commercial IL, bmim.BF₄, not only enhanced GNP dispersion but also influenced the morphology of the PLA/EVA composite, improving the continuity of EVA phase. This modification significantly lowered the composite's electrical percolation threshold and endowed the material with outstanding electromagnetic absorptivity properties, achieving a reflection loss (RL) below −30 dB and an effective absorption bandwidth (EAB) of 3.67 GHz, covering nearly the entire Ku-band frequency range, with only 5.0 wt% of treated GNP. This study provides novel insights into GNP exfoliation techniques utilizing environmentally friendly solvent and surfactants, and the fabrication of partially biodegradable polymeric composites for electromagnetic absorption applications, such as packaging in electronic devices.

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离子液体辅助石墨烯液相剥离及改善PLA/EVA/石墨烯复合材料的电、电磁性能

由于填料和聚合物之间表面能的差异，碳质填料在聚合物基体中的分散提出了一个重大的挑战。在这项研究中，采用了一种简单而经济的方法，使用液相剥离（LPE）技术，以离子液体（ILs）作为表面活性剂，在水中剥离石墨烯纳米片（GNP）。随后，将处理过的石墨烯掺入PLA/EVA （60:40 wt%）复合材料中，评估其流变学和交流（AC）电性能，以及X和Ku波段（8.2至18 GHz）的电磁吸收率。拉曼光谱证实了GNP结构的改变，表明剥离成功。傅里叶变换红外光谱（FTIR）和热重分析（TGA）表明，一部分IL粘附在GNP颗粒上，从而被纳入聚合物复合材料中。合成的咪唑磺胺基IL促进了更强烈的剥落和颗粒破碎，导致复合材料的电导率和电磁吸收率降低。相比之下，商业IL， bmim。BF4不仅增强了GNP的分散性，而且影响了PLA/EVA复合材料的形貌，提高了EVA相的连续性。这种改性显著降低了复合材料的电渗透阈值，并赋予材料出色的电磁吸收性能，实现了反射损耗（RL）低于- 30 dB，有效吸收带宽（EAB）为3.67 GHz，覆盖了几乎整个ku波段频率范围，仅占处理GNP的5.0 wt%。这项研究为利用环境友好型溶剂和表面活性剂的GNP剥离技术提供了新的见解，并为电磁吸收应用（如电子设备包装）制造了部分可生物降解的聚合物复合材料。

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来源期刊

FlatChem Multiple-

CiteScore

8.40

自引率

6.50%

发文量

104

审稿时长

26 days

期刊介绍： FlatChem - Chemistry of Flat Materials, a new voice in the community, publishes original and significant, cutting-edge research related to the chemistry of graphene and related 2D & layered materials. The overall aim of the journal is to combine the chemistry and applications of these materials, where the submission of communications, full papers, and concepts should contain chemistry in a materials context, which can be both experimental and/or theoretical. In addition to original research articles, FlatChem also offers reviews, minireviews, highlights and perspectives on the future of this research area with the scientific leaders in fields related to Flat Materials. Topics of interest include, but are not limited to, the following: -Design, synthesis, applications and investigation of graphene, graphene related materials and other 2D & layered materials (for example Silicene, Germanene, Phosphorene, MXenes, Boron nitride, Transition metal dichalcogenides) -Characterization of these materials using all forms of spectroscopy and microscopy techniques -Chemical modification or functionalization and dispersion of these materials, as well as interactions with other materials -Exploring the surface chemistry of these materials for applications in: Sensors or detectors in electrochemical/Lab on a Chip devices, Composite materials, Membranes, Environment technology, Catalysis for energy storage and conversion (for example fuel cells, supercapacitors, batteries, hydrogen storage), Biomedical technology (drug delivery, biosensing, bioimaging)