Interaction effects of silica incorporation and processing parameters on dielectric loss in pineapple leaf-epoxy composites at 5 GHz
DOI:
https://doi.org/10.15282/Keywords:
Bio-based dielectric composite, Natural fiber composite, Microwave substrate, Loss tangent, Two-level factorial analysisAbstract
Bio-based dielectric composites have attracted increasing interest as sustainable substitutes for conventional microwave materials, but controlling dielectric loss through the interplay of processing and formulation parameters is still a significant challenge. This work studies the interaction effects of silica addition and processing parameters on the dielectric properties of pineapple leaf-epoxy composites at 5 GHz. The effects of volume of sodium hydroxide solution, soaking time, silica loading, and pineapple leaf fiber powder loading were evaluated using a two-level factorial analysis. Dielectric characterization was performed using a vector network analyzer and a rectangular waveguide. The loss tangent values of the resulting composites were 0.00959 to 0.05894, and the permittivity values were 2.83 to 3.39. The analysis of variance confirmed the statistical significance of the developed factorial model (p = 0.0064) with an adjusted R² of 0.9999. Additionally, the formulated compositions investigated, the smallest loss tangent of 9.59122×10-3 was obtained using 450 mL sodium hydroxide solution, 30 min soaking time, 4 g silica loading, and 30 g pineapple leaf fiber powder loading. The results suggest that the dielectric performance of pineapple leaf-epoxy composites is controlled by the interplay of processing conditions and material formulation, providing therefore a systematic framework for the development of sustainable dielectric materials for microwave substrate applications.
Downloads
References
[1] M. S. A. Karim, N. Zainol, N. H. Aziz, M. J. M. Fikry, and N. A. T. Yusof, “Surface analysis of pineapple leaves pulp-based dielectric composite material and its dielectric performance,” Next Materials, vol. 8, p. 100706, Jul. 2025, doi: 10.1016/j.nxmate.2025.100706.
[2] N. H. Abu Bakar and A. Abu Bakar, “Dielectric characterization of Flexible Pineapple Leaf Fiber (PALF) Reinforced Polydimethylsiloxane (PDMS) composite as a potential antenna substrate for wearable antenna application,” in Innovation in Action: Turning Ideas into Reality, Seremban, Malaysia: Universiti Teknologi MARA, Negeri Sembilan, 2025, pp. 235–239.
[3] M. Sethupathi, M. V. Khumalo, S. J. Skosana, and S. Muniyasamy, “Recent developments of pineapple leaf fiber (PALF) utilization in the polymer composites—a review,” Separations, vol. 11, no. 8, p. 245, Aug. 2024, doi: 10.3390/separations11080245.
[4] N. A. T. Yusof, N. Zainol, N. H. Aziz, R. D. Giamasrow, A. N. Azman, and M. S. A. Karim, “A review of morphological, structural, dielectric, and electrical properties of renewable plant-based dielectric composite materials,” J. Mater. Sci.: Mater. Electron., vol. 37, no. 16, p. 1274, Jun. 2026, doi: 10.1007/s10854-026-1274-x.
[5] A. N. Azman, N. Mustafa, R. D. Giamasrow, N. A. T. Yusof, N. Zainol, and M. S. A. Karim, “Effect of factors on dielectric properties of pineapple leaf for microwave application,” Mater. Today: Proc., vol. 110, pp. 127–133, 2024, doi: 10.1016/j.matpr.2024.03.110.
[6] J. Liu, P. Ming, Z. Zhou, T. Zhang, Q. Liu, and B. Du, “Review of Preparing Low-Dielectric Epoxy Resin Composites,” Coatings, vol. 16, no. 1, p. 118, Jan. 2026, doi: 10.3390/coatings16010118.
[7] F. Fernández-Gil, N. Rosales-Cuello, and H. Palza, “High-performance piezoelectric nanogenerators based on polymer composites with conductive particles—from interfacial polarization to piezotronic effects,” Emergent Mater., vol. 9, no. 1, p. 16, Feb. 2026, doi: 10.1007/s42247-026-0016-y.
[8] N. Zainol, N. H. Aziz, Y. N. Zaidy, and N. F. N. Rasid, “Determination of Significant Factors and Optimum Condition for Pineapple Leaf Fiber Extraction as Potential Dielectric Material,” Curr. Appl. Sci. Technol., vol. 24, p. e0261782, Nov. 2024.
[9] T. Akarapoowadol, K. L. Goh, and T. Amornsakchai, “Effect of Alkali Treatment on the Mechanical and Structural Properties of Pineapple Leaf Fiber for Epoxy Composite Reinforcement,” ACS Omega, vol. 11, no. 2, pp. 1420–1431, 2026, doi: 10.1021/acsomega.6b0142.
[10] M. S. B. A. Karim, N. B. A. T. Yusof, and T. Kitazawa, “Scattering analysis of rectangular cavity with input and output waveguides and its application to material characterization,” in Proc. 2017 IEEE Asia Pacific Microwave Conf. (APMC), 2017, pp. 588–591, doi: 10.1109/APMC.2017.8251510.
[11] M. S. B. A. Karim, Y. Konishi, K. Harafuji, and T. Kitazawa, “Determination of complex permittivities of layered materials using waveguide measurements,” IEEE Trans. Microw. Theory Techn., vol. 62, no. 9, pp. 2140–2148, Sep. 2014, doi: 10.1109/TMTT.2014.2332301.
[12] D. Munalli, M. T. Al Qaseer, and R. Zoughi, “Modified waveguide-based method for microwave characterization of high-loss materials,” IEEE Trans. Instrum. Meas., vol. 71, pp. 1–10, 2022, doi: 10.1109/TIM.2022.3168904.
[13] I. Haider, I. H. Gul, M. A. Umer, and M. M. Baig, “A low-cost silica fiber/epoxy composite with excellent dielectric properties, and good mechanical and thermal stability,” Materials, vol. 16, no. 23, p. 7410, Nov. 2023, doi: 10.3390/ma16237410.
[14] P. P. Singh, A. K. Dash, and G. Nath, “Dielectric characterization analysis of natural fiber based hybrid composite for microwave absorption in X-band frequency,” Appl. Phys. A, vol. 130, no. 3, p. 171, Mar. 2024, doi: 10.1007/s00339-024-07312-5.
[15] T. Eleutério, M. J. Trota, M. G. Meirelles, and H. C. Vasconcelos, “A review of natural fibers: classification, composition, extraction, treatments, and applications,” Fibers, vol. 13, no. 9, p. 119, Sep. 2025, doi: 10.3390/fib13090119.
[16] G. Torğut and R. İncesu, “Response surface method (RSM) for optimization of electrical properties of polymer/CdS composites for dielectric capacitors,” Macromol. Res., vol. 33, no. 9, pp. 1245–1262, Sep. 2025, doi: 10.1007/s13233-025-1245-x.
[17] K. Keshyagol, S. Hiremath, V. HM, and P. Hiremath, “A Review on Dielectric Materials and Composites: Polarisation Effects, Synthesis Methods and Applications,” IET Nanodielectrics, vol. 9, no. 1, p. e70026, 2026, doi: 10.1049/nde2.12026.
[18] A. Beno, “Stacked natural-fiber fabric mats as green super-substrates: integrated characterization and antenna realizations for smart bandages and 5G wearable IoT,” Mater. Res. Express, vol. 13, no. 4, p. 046301, Apr. 2026, doi: 10.1088/2053-1591/ab0463.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 The Author(s)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
