Title: A GENERAL SEM IMAGE–BASED DISPERSION INDEX FOR QUANTITATIVE ASSESSMENT OF NANOPARTICLE DISPERSION IN NANOCOMPOSITES

Authors: Piyush Gaur, Punya Bansal, Purva Uniyal, Mradula Sharma, Vikas Kumar, Jitendra Yadav

DOI: https://doi.org/10.33599/GL.2026.INCOMAT.TP26-0021

Abstract: Nanoparticle dispersion strongly influences the performance of polymer nanocomposites, as non-uniform dispersion and agglomeration create localized stress concentrations, reduce interfacial load transfer, and promote premature microcracking, resulting in property scatter and poor repeatability even at identical filler loadings. In multifunctional composites, uneven dispersion also disrupts conductive and thermal pathways, reducing electrical and thermal stability. To address this, the present work introduces a deterministic and reproducible SEM image-analysis framework for calculating a Dispersion Index (DI) to quantitatively evaluate nanoparticle dispersion in filled composites. The workflow combines percentile-based contrast normalization, dual adaptive-threshold segmentation with morphological refinement, particle and flake feature extraction, and dispersion quantification based on tile-wise area uniformity, nearest-neighbour deviation from complete spatial randomness, and size-variability penalties. A DBSCAN-based clustering step is included to flag agglomerated states for quality assurance. Applied to graphene–epoxy nanocomposites with varying filler loadings and processing conditions, the method distinguishes well-dispersed and agglomerated microstructures and shows good agreement with dispersion-sensitive mechanical response trends, providing a practical tool for dispersion benchmarking and process optimization.

References: [1] M. Altin Karataş and H. Gökkaya, ‘A review on machinability of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composite materials’, Def. Technol., vol. 14, no. 4, pp. 318–326, Aug. 2018, doi: 10.1016/j.dt.2018.02.001. [2] N. F. I. Azman, S. A. Zuhairi, C. T. Ratnam, Y. Yaakob, and M. S. Mamat, ‘Incorporation of Multiwalled Carbon Nanotubes and Graphene Nanoplatelets on the Morphology and Properties of Polyethylene Terephthalate Nanocomposites’, J. Nanomater., vol. 2021, p. e6633604, May 2021, doi: 10.1155/2021/6633604. [3] M. Bashar, P. Mertiny, and U. Sundararaj, ‘Effect of Nanocomposite Structures on Fracture Behavior of Epoxy-Clay Nanocomposites Prepared by Different Dispersion Methods’, J. Nanomater., vol. 2014, Jun. 2014, doi: 10.1155/2014/312813. [4] A. Tunell et al., ‘Nanoparticle dispersion and separation in superhydrophilic nanostructures’, RSC Appl. Interfaces, vol. 2, no. 5, pp. 1199–1208, Sep. 2025, doi: 10.1039/D5LF00089K. [5] S. Zhang and C. Wang, ‘Effect of stirring speed on particle dispersion in silica synthesis’, Nano-Struct. Nano-Objects, vol. 35, p. 100994, Jul. 2023, doi: 10.1016/j.nanoso.2023.100994. [6] ‘ISO 11345:2006’, ISO. Accessed: Feb. 12, 2026. [Online]. Available: https://www.iso.org/standard/40388.html [7] ‘Standard Test Methods for Carbon Black—Dispersion in Rubber’. Accessed: Feb. 12, 2026. [Online]. Available: https://store.astm.org/d2663-14r19e01.html [8] M. D. Haslam and B. Raeymaekers, ‘A composite index to quantify dispersion of carbon nanotubes in polymer-based composite materials’, Compos. Part B Eng., vol. 55, pp. 16–21, Dec. 2013, doi: 10.1016/j.compositesb.2013.05.038. [9] S. A. Shojaee, A. Zandiatashbar, N. Koratkar, and D. A. Lucca, ‘Raman spectroscopic imaging of graphene dispersion in polymer composites’, Carbon, vol. 62, pp. 510–513, Oct. 2013, doi: 10.1016/j.carbon.2013.05.068. [10] M. Gresil, Z. Wang, Q.-A. Poutrel, and C. Soutis, ‘Thermal Diffusivity Mapping of Graphene Based Polymer Nanocomposites’, Sci. Rep., vol. 7, no. 1, p. 5536, Jul. 2017, doi: 10.1038/s41598-017-05866-0. [11] K. Anane-Fenin, E. T. Akinlabi, and N. Perry, ‘A Method for the Quantification of Nanoparticle Dispersion in Nanocomposites Based on Fractal Dimension’, in Advances in Material Sciences and Engineering, M. Awang, S. S. Emamian, and F. Yusof, Eds, Singapore: Springer, 2020, pp. 555–564. doi: 10.1007/978-981-13-8297-0_57. [12] F. Boué, ‘3D Characterization of Nanoparticle Dispersion in Polymer Nanocomposites by TEM Tomography’, Microsc. Microanal., doi: 10.1017/S1431927613004662. [13] B. Luo, X. Wang, M. Tian, Z. Cai, and L. Li, ‘Homogeneity quantification of nanoparticles dispersion in composite materials’, Polym. Compos., vol. 40, no. 3, pp. 1000–1005, 2019, doi: 10.1002/pc.24776. [14] D. Mondal and T. L. Willett, ‘Dispersion Strategy improves the mechanical properties of 3D-Printed biopolymer nanocomposite’, Compos. Part B Eng., vol. 283, p. 111680, Aug. 2024, doi: 10.1016/j.compositesb.2024.111680. [15] N. Montinaro, M. Fustaino, D. Bellisario, F. Quadrini, L. Santo, and A. Pantano, ‘Testing the Dispersion of Nanoparticles in a Nanocomposite with an Ultra-Low Fill Content Using a Novel Non-Destructive Evaluation Technique’, Materials, vol. 15, no. 3, p. 1208, Jan. 2022, doi: 10.3390/ma15031208.

Conference: INCOMAT 2026

Publication Date: 2026/03/13

SKU: INCOMAT.TP26-0021

Pages: 15

Price: $30.00