EMI shielding of ABS composites filled with different temperature-treated equal-quantity charcoals

Electromagnetic interference (EMI) shielding is a critical area of research in materials science and electrical engineering. Current shielding materials often rely on conductive fillers such as carbon-based compounds. While prior research has shown that carbonized materials can improve EMI performance, the specific effects of carbonization temperature on shielding effectiveness remain unclear. Existing studies have explored various filler types and concentrations but have not focused on the impact of equal-quantity charcoals treated at different temperatures. This gap motivated the investigation into how carbonization temperature influences the shielding behavior of acrylonitrile-butadiene-styrene (ABS) composites. The need to develop cost-effective, high-performance shielding materials has driven interest in optimizing filler treatment conditions. No prior work had resolved the relationship between carbonization temperature and EMI shielding in equal-quantity charcoal composites. This uncertainty drove the current study to explore the role of temperature-treated charcoals in enhancing shielding effectiveness. The goal is to determine whether temperature treatment can be used to tailor composite properties for specific shielding applications.

The aim of this study was to evaluate how carbonization temperature affects the electromagnetic shielding effectiveness of ABS composites filled with equal-quantity charcoals. The specific problem addressed is the lack of understanding of how temperature treatment of charcoals influences shielding performance when used in polymer composites. The motivation stems from the need to develop materials that can provide high EMI shielding with minimal filler content. By using equal-quantity charcoals treated at different temperatures, the study sought to determine whether temperature treatment can enhance shielding effectiveness. The researchers proposed that increased carbonization temperatures would improve conductivity and absorption behavior in the composites. This approach allows for the development of custom-made shielding materials without altering the filler quantity. The study's design focused on comparing composites with charcoals treated at temperatures ranging from 500 °C to 1100 °C. The findings could inform the production of optimized shielding composites for electronic and industrial applications.

The study involved preparing ABS composites by dry mixing equal-quantity charcoals (20 wt%) treated at different temperatures. The charcoals were carbonized at temperatures ranging from 500 °C to 1100 °C in 100 °C increments. After treatment, the charcoals were mixed with ABS and hot-compressed under identical processing conditions. The resulting composites were analyzed for electromagnetic shielding effectiveness in the X-band frequency range (8.2-12.4 GHz). Conductivity measurements were conducted to assess the electrical properties of the composites. Scanning electron microscopy (SEM) was used to examine the microstructure and porosity of the charcoals. Dielectric behavior was evaluated by measuring dielectric loss and permittivity at varying frequencies. The experimental setup ensured that all samples were processed under the same conditions to isolate the effects of temperature treatment. The data collected were used to correlate carbonization temperature with shielding performance and material properties.

The highest shielding effectiveness was observed in composites containing charcoals treated at 1100 °C, with an absorption-dominated shielding effectiveness of approximately 36.8 dB at 11.6 GHz. As the carbonization temperature increased, the conductivity of the composites also increased, leading to improved absorption behavior. The study found that higher treatment temperatures resulted in increased porosity and dielectric losses in the charcoals. Dielectric loss (ε'') decreased with increasing frequency, indicating frequency-dependent behavior. The composites with higher temperature-treated charcoals showed a significant enhancement in shielding effectiveness compared to those with lower temperature-treated charcoals. SEM analysis confirmed the increase in porosity with higher treatment temperatures. The results suggest that temperature treatment is a key factor in determining the shielding performance of the composites. These findings provide evidence that higher carbonization temperatures can be used to tailor composite properties for EMI shielding applications.

The study demonstrates that increasing the carbonization temperature of charcoals used in ABS composites leads to improved electromagnetic shielding effectiveness. The authors propose that this is due to enhanced conductivity and absorption behavior in composites containing higher temperature-treated charcoals. The results suggest that temperature treatment is a viable method for tailoring composite properties to meet specific shielding requirements. The composites with 1100 °C-treated charcoals showed the highest shielding effectiveness, reaching approximately 36.8 dB at 11.6 GHz. The observed increase in porosity and dielectric losses with higher treatment temperatures supports the proposed mechanism for improved shielding. The findings indicate that equal-quantity charcoals can be used to develop custom-made shielding composites without altering filler content. The study highlights the importance of carbonization temperature in determining the performance of shielding materials. These conclusions align with the observed data and the authors' stated objectives.