journal article·2026-06Open access

Enhancing Thermal Conductivity in Polymer Blends with In-Plane Oriented Boron Nitride

Geeta Pokhrel, Gavin J. Anzaldi, Shanmukhi Sripada, Amy M. Marconnet, Chelsea S. Davis, John A. Howarter

Applied Composite Materials· Volume 33· Issue 3

Abstract

Abstract Polymer nanocomposites for thermal management applications, such as flexible electronics, sensors, and stretchable devices, require enhanced thermal conductivity while maintaining mechanical flexibility. However, achieving a balance between thermal and mechanical properties remains a significant challenge, as improving one property often compromises the other. In this study, we design and fabricate elastic, compliant, and moldable polymer blend nanocomposites with enhanced thermal conductivity. The nanocomposite system comprises dynamically vulcanized rubbery polyisoprene (PI) as the continuous matrix and stiffer polystyrene (PS) as the dispersed phase, along with two-dimensional (2D) boron nitride (BN) as the thermally conductive filler. The PI matrix is selectively crosslinked, whereas the PS phase remains non-crosslinked, making the composites processable. BN is uniformly distributed in both polymer phases to facilitate effective thermal conduction. A hot-pressing step following extrusion aligns the 2D BN predominantly in the in-plane direction, inducing anisotropy in both thermal conductivity and elastic modulus. At a BN loading of 40 vol%, the in-plane thermal conductivity increases by approximately sevenfold and the cross-plane thermal conductivity by twofold compared to the unfilled PS/PI blend. Similarly, the in-plane elastic modulus is enhanced by approximately 10 times and the cross-plane modulus by about 2.5 times. The overall modulus remains below 8 MPa across all compositions, ensuring that the composites remain soft and compliant. We anticipate that the materials developed in this study can be modified for the next generation of thermally conductive yet mechanically flexible applications.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Thermal properties of materials · Thermal Radiation and Cooling Technologies · Carbon Nanotubes in Composites

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

References (58)

Show source-provided references
1. Guo, Y., Zhou, Y., Xu, Y.: Engineering polymers with metal-like thermal conductivity—Present status and future perspectives. Polymer (2021). https://doi.org/10.1016/j.polymer.2021.12416810.1016/j.polymer.2021.124168 ↗
2. Fang, Y., Chen, G., Bick, M., Chen, J.: Smart textiles for personalized thermoregulation. Chem. Soc. Rev. 50(17), 9357–9374 (2021). https://doi.org/10.1039/D1CS00003A10.1039/D1CS00003A ↗
3. Tan, D.Q.: The search for enhanced dielectric strength of polymer-based dielectrics: A focused review on polymer nanocomposites. J. Appl. Polym. Sci. 137(33), 49379 (2020). https://doi.org/10.1002/app.4937910.1002/app.49379 ↗
4. Chen, X., Su, Y., Reay, D., Riffat, S.: Recent research developments in polymer heat exchangers – A review. Renewable and Sustainable Energy Reviews 60, 1367–1386 (2016). https://doi.org/10.1016/j.rser.2016.03.02410.1016/j.rser.2016.03.024 ↗
5. Sahu, B.B., Moharana, S., Behera, P.K.: Elastomeric-Based Composite Materials for Engineering Applications. In Polymer Composites: Fundamentals and Applications, Singapore: Springer Nat. Singapore. 329–355 (2024)10.1007/978-981-97-2075-0_11 ↗
6. Deeba, F., Shrivastava, K., Bafna, M., Jain, A.: Tuning of Dielectric Properties of Polymers by Composite Formation: The Effect of Inorganic Fillers Addition. J. Compos. Sci. 6(12), 355 (2022). https://doi.org/10.3390/jcs612035510.3390/jcs6120355 ↗
7. Han, R., Wang, Z., Zhang, Y., Niu, K.: Thermal stability of CeO2/graphene/phenyl silicone rubber composites. Polym. Test. (2019). https://doi.org/10.1016/j.polymertesting.2019.02.02710.1016/j.polymertesting.2019.02.027 ↗
8. Ma, Y., Meng, J., Xia, L.: Preparation and properties of HDPE/MVQ thermoplastic vulcanizate with low-temperature-resistant super toughness and shape memory properties. Eur. Polym. J. (2022). https://doi.org/10.1016/j.eurpolymj.2022.11153010.1016/j.eurpolymj.2022.111530 ↗
9. Xiong, J., Cui, R., Xu, C., Ding, J., Chen, Y.: Silica-reinforced ethylene propylene diene monomer/polypropylene thermoplastic vulcanizates with interfacial compatibilized by methylacrylate. Polym. Compos. 42(2), 701–713 (2021). https://doi.org/10.1002/pc.2585910.1002/pc.25859 ↗
10. Ning, N., Li, S., Wu, H., Tian, H., Yao, P., Hu, G.H., Tian, M., Zhang, L.: Preparation, microstructure, and microstructure-properties relationship of thermoplastic vulcanizates (TPVs): A review. Progress in Polymer Science 79, 61–97 (2018). https://doi.org/10.1016/j.progpolymsci.2017.11.00310.1016/j.progpolymsci.2017.11.003 ↗
11. Cui, Z., Wang, J., Wei, L., Liu, Y., Du, A.: Effect of dynamic vulcanization time on the performance of thermoplastic vulcanizates based on hydrogenated acrylonitrile butadiene rubber/thermoplastic polyester elastomer. J. Appl. Polym. Sci. (2023). https://doi.org/10.1002/app.5470310.1002/app.54703 ↗
12. Zhao, G., Tian, K., Pan, Q., Zhang, Q., Deng, H., Fu, Q.: A novel method to incorporate functional filler into TPSiV for balanced physical properties. Compos. Sci. Technol. 213, 108925 (2021). https://doi.org/10.1016/j.compscitech.2021.10892510.1016/j.compscitech.2021.108925 ↗
13. Tang, Y., Lu, K., Cao, X., Li, Y.: Nanostructured Thermoplastic Vulcanizates by Selectively Cross-Linking a Thermoplastic Blend with Similar Chemical Structures. Ind. Eng. Chem. Res. 52(35), 12613–12621 (2013). https://doi.org/10.1021/ie401853k10.1021/ie401853k ↗
14. Fazli, A., Rodrigue, D.: Waste Rubber Recycling: A Review on the Evolution and Properties of Thermoplastic Elastomers. Materials. 13(3), 782 (2020). https://doi.org/10.3390/ma1303078210.3390/ma13030782 ↗
15. Tang, Q., Hu, S., Han, L., Zong, C., Sun, J.: Morphological Evolution and Damping Properties of Dynamically Vulcanized Butyl Rubber/Polypropylene Thermoplastic Elastomers. Polymers. 14(13), 2740 (2022). https://doi.org/10.3390/polym1413274010.3390/polym14132740 ↗
16. Bhattacharya, A.B., Raju, A.T., Chatterjee, T., Naskar, K.: Development and characterizations of ultra-high molecular weight EPDM/PP based TPV nanocomposites for automotive appplications. Polym. Compos. 41(12), 4950–4962 (2020). https://doi.org/10.1002/pc.2576510.1002/pc.25765 ↗
17. Antunes, C.F., Machado, A.V., Duin, M.V.: Morphology development and phase inversion during dynamic vulcanisation of EPDM/PP blends. Eur. Polym. J. (2011). https://doi.org/10.1016/j.eurpolymj.2011.04.00510.1016/j.eurpolymj.2011.04.005 ↗
18. Chen, Y., Yuan, D., Xu, C.: Dynamically Vulcanized Biobased Polylactide/Natural Rubber Blend Material with Continuous Cross-Linked Rubber Phase. ACS Appl. Mater. Interfaces (2014). https://doi.org/10.1021/am500476610.1021/am5004766 ↗
19. Belhaoues, A., Benmesli, S., Abderrahmane, S.B.: The effect of physical compatibilization and dynamic vulcanization on the properties of thermoplastic vulcanizates derived from polypropylene and natural rubber blends. J. Thermoplast Compos. Mater. 37(12) (2024). https://doi.org/10.1177/0892705724124469710.1177/08927057241244697 ↗
20. Haghnegahdar, M., Naderi, G., Ghoreishy, M.H.R.: Fracture toughness and deformation mechanism of un-vulcanized and dynamically vulcanized polypropylene/ethylene propylene diene monomer/graphene nanocomposites. Compos. Sci. Technol. 141, 83–98 (2017). https://doi.org/10.1016/j.compscitech.2017.01.01510.1016/j.compscitech.2017.01.015 ↗
21. Wang, Y., Gong, Z., Xu, C., Chen, Y.: Poly (vinylidene fluoride)/fluororubber/silicone rubber thermoplastic vulcanizates prepared through core-shell dynamic vulcanization: Formation of different rubber/plastic interfaces via controlling the core from soft to hard. Mater. Chem. Phys. 195, 123–131 (2017). https://doi.org/10.1016/j.matchemphys.2017.04.01610.1016/j.matchemphys.2017.04.016 ↗
22. Pokhrel, G., Howarter, J.A., Wilson, M.C., Davis, C.S.: Resilient Polymer Nanocomposites for Type II Thermal Interface Materials, pp. 1–7. IEEE (2024). https://doi.org/10.1109/ITherm55375.2024.1070959910.1109/ITherm55375.2024.10709599 ↗
23. Jang, W., Lee, S., Kim, N.R., Koo, H., Yu, J., Yang, C.M.: Eco-friendly and scalable strategy to design electrically insulating boron nitride/polymer composites with high through-plane thermal conductivity. Compos. Part. B: Eng. 248, 110355 (2023). https://doi.org/10.1016/j.compositesb.2022.11035510.1016/j.compositesb.2022.110355 ↗
24. Li, M., Wang, M., Hou, X., Zhan, Z., Wang, H., Fu, H., Lin, C.T., Fu, L., Jiang, N., Yu, J.: Highly thermal conductive and electrical insulating polymer composites with boron nitride. Compos. Part. B: Eng. 184, 107746 (2020). https://doi.org/10.1016/j.compositesb.2020.10774610.1016/j.compositesb.2020.107746 ↗
25. Cai, Q., Scullion, D., Gan, W., Falin, A., Zhang, S., Watanabe, K., Taniguchi, T., Chen, Y., Santos, E.J.G., Li, L.H.: High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion. Sci. Adv. (2019). https://doi.org/10.1126/sciadv.aav012910.1126/sciadv.aav0129 ↗
26. Steinborn, C., Herrmann, M., Keitel, U., Schönecker, A., Räthel, J., Rafaja, D., Eichler, J.: Correlation between microstructure and electrical resistivity of hexagonal boron nitride ceramics. J. Eur. Ceram. Soc. (2013). https://doi.org/10.1016/j.jeurceramsoc.2012.11.02410.1016/j.jeurceramsoc.2012.11.024 ↗
27. Pokhrel, G., Christ, N.M., Wilson, M.C., Howarter, J.A., Davis, C.S.: Mechanical Deformation of Polymer Blend Thin Films Reinforced with Boron Nitride. ACS Appl. Polym. Mater. (2024). https://doi.org/10.1021/acsapm.4c0153110.1021/acsapm.4c01531 ↗
28. Zhan, K., Chen, Y., Xiong, Z., Zhang, Y., Ding, S., Zhen, F., Liu, Z., Wei, Q., Liu, M., Sun, B., Cheng, H.M., Qiu, L.: Low thermal contact resistance boron nitride nanosheets composites enabled by interfacial arc-like phonon bridge. Nat. Commun. 15, 2905 (2024). https://www.nature.com/articles/s41467-024-47147-110.1038/s41467-024-47147-1 ↗
29. Ye, W., Wang, Z., Zeng, X., Ren, L., Sun, R., Wen, Z., Zeng, X.: Study on the influence of different filler fractions on the properties of thermal interface materials. IEEE. (2021). https://ieeexplore.ieee.org/document/956805410.1109/ICEPT52650.2021.9568054 ↗
30. Sarvar, F., Whalley, D., Conway, C.: Thermal interface materials – A review of the state of the art. IEEE. (2006). https://ieeexplore.ieee.org/document/406090310.1109/ESTC.2006.280178 ↗
31. Dai, W., Ren, X.J., Yan, Q., Wang, S., Yang, M., Lv, L., Ying, J., Chen, L., Tao, P., Sun, L., Xue, C., Yu, J., Song, C., Nishimura, K., Jiang, N., Lin, C.T.: Ultralow Interfacial Thermal Resistance of Graphene Thermal Interface Materials with Surface Metal Liquefaction. Nano-Micro Letters (2023). https://doi.org/10.1007/s40820-022-00979-210.1007/s40820-022-00979-2 ↗
32. Chung, D.D.L.: Performance of Thermal Interface Materials. Small 18(16), 2200693 (2022). https://doi.org/10.1002/smll.20220069310.1002/smll.202200693 ↗
33. Subramanian, V., Sanchez, J., Bautista, J., He, Y., Wang, J., Das, A., Schuldes, J.G.R., Yazzie, K., Dhavaleswarapu, H.K., Malatkar, P.: Mechanical Characterization of Thermal Interface Materials and Its Challenges. J. Electron. Packag Trans. ASME. (2019). https://doi.org/10.1115/1.404280510.1115/1.4042805 ↗
34. Pokhrel, G., Jo, H., Christ, N.M., Son, H., Howarter, J.A., Davis, C.S.: Mechanical Deformation Behavior of Polymer Blend Thin Films. Macromol. Rapid Commun. (2025). https://doi.org/10.1002/marc.20240073610.1002/marc.202400736 ↗
35. Chandresh, M.P., Roopa, S., Dechamma, C.D.: PS/LIR dynamic vulcanization: new approach in TPV development using liquid rubber for impact modification. Polym. Bull 81(6), 5443–5457 (2024). https://doi.org/10.1007/s00289-023-04953-910.1007/s00289-023-04953-9 ↗
36. Nabil, H., Ismail, H., Azura, A.R.: Optimization of accelerators on curing characteristics, tensile, and dynamic mechanical properties of (natural rubber)/(recycled ethylene-propylene‐diene‐monomer) blends. J. Vinyl Add Tech. 21(2), 79–88 (2015). https://doi.org/10.1002/vnl.2135810.1002/vnl.21358 ↗
37. Wang, X., Wu, P.: Preparation of Highly Thermally Conductive Polymer Composite at Low Filler Content via a Self-Assembly Process between Polystyrene Microspheres and Boron Nitride Nanosheets. ACS Appl. Mater. Interfaces. (2017). https://doi.org/10.1021/acsami.7b0476810.1021/acsami.7b04768 ↗
38. Gao, H.L., Chen, S.M., Mao, L.B., Song, Z.Q., Yao, H.B., Cölfen, H., Luo, X.S., Zhang, F., Pan, Z., Meng, Y.F., Ni, Y., Yu, S.H.: Mass production of bulk artificial nacre with excellent mechanical properties. Nat. Commun. 8(1) (2017). https://doi.org/10.1038/s41467-017-00392-z10.1038/s41467-017-00392-z ↗
39. Ennis, H.B., Ade, H.: Direct spincasting of polystyrene thin films onto poly(methyl methacrylate). J. Polym. Sci., Part B: Polym. Phys. 44(22) (2006). https://doi.org/10.1002/polb.2097610.1002/polb.20976 ↗
40. Yan, J., Zhang, Z., Man, J., Sun, J., Zhen, R., Liu, X.A.: Parameter Identification of the Mooney–Rivlin Model for Rubber Mounts Subject to Multiaxial Load. J. Vib. Eng. Technol. (2025). https://doi.org/10.1007/s42417-024-01594-810.1007/s42417-024-01594-8 ↗
41. Gomez-Jimenez, S., Saucedo-Anaya, T., Guerrero-Mendez, C., Robles-Guerrero, A., Silva-Acosta, L., Navarro-Solis, D., Lopez-Betancur, D., Contreras Rodríguez, A.R.: Mooney–Rivlin Parameter Determination Model as a Function of Temperature in Vulcanized Rubber Based on Molecular Dynamics Simulations. Mater 17(13), 3252 (2024). https://doi.org/10.3390/ma1713325210.3390/ma17133252 ↗
42. Gaitonde, A.U., Candadai, A.A., Weibel, J.A., Marconnet, A.M.: A laser-based Ångstrom method for in-plane thermal characterization of isotropic and anisotropic materials using infrared imaging. Rev. Sci. Instrum. (2023). https://doi.org/10.1063/5.014965910.1063/5.0149659 ↗
43. Gaitonde, A., Nimmagadda, A., Marconnet, A.M.: Measurement of interfacial thermal conductance in Lithium ion batteries. J. Power Sources 343, 431–436 (2017). https://doi.org/10.1016/j.jpowsour.2017.01.01910.1016/j.jpowsour.2017.01.019 ↗
44. Kantharaj, R., Srivastava, I., Thaker, K.R., Gaitonde, A.U., Bruce, A., Howarter, J.A., Fisher, T.S., Marconnet, A.M.: Thermal conduction in graphite flake-epoxy composites using infrared microscopy. IEEE. (2017). https://doi.org/10.1109/itherm.2017.802396010.1109/itherm.2017.8023960 ↗
45. A. E1269-24: Standard Test Method for Determining Specific Heat Capacity by Differential Scanning Calorimetry, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428 – 2959. United States (2024)
46. Xu, X., Ma, L., Liu, C.: Bio-based polylactic acid or epoxy natural rubber thermoplastic vulcanizates with dual interfacial compatibilization networks. Polymer Engineering & Science 62(6), 1987–1998 (2022). https://doi.org/10.1002/pen.2598110.1002/pen.25981 ↗
47. Gong, Z., Huang, J., Fan, J., Chen, X., Wang, H., Chen, Y.: Super-Tough Poly(lactic Acid)-Based Thermoplastic Vulcanizate Based on Selective Dispersion and In Situ Compatibilization of Commercial Reinforcing Fillers and Its Application in Three-Dimensional Printing. Ind. Eng. Chem. Res. (2021). https://doi.org/10.1021/acs.iecr.1c0339210.1021/acs.iecr.1c03392 ↗
48. Jiang, G., Zhang, J., Ding, J., Chen, Y.: Design of PLA/NR thermoplastic vulcanizates with balanced stiffness-toughness based on rubber reinforcement and selective distribution of modified silica. Polym. Adv. Technol 32(6), 2487–2498 (2021). https://doi.org/10.1002/pat.527910.1002/pat.5279 ↗
49. Fenouillot, F., Cassagnau, P., Majesté, J.C.: Uneven distribution of nanoparticles in immiscible fluids: Morphology development in polymer blends. Polymer (2009). https://doi.org/10.1016/j.polymer.2008.12.02910.1016/j.polymer.2008.12.029 ↗
50. Hu, J., Huang, Y., Zeng, X., Li, Q., Ren, L., Sun, R., Xu, J.B., Wong, C.P.: Polymer composite with enhanced thermal conductivity and mechanical strength through orientation manipulating of BN. Compos. Sci. Technol. 160, 127–137 (2018). https://doi.org/10.1016/j.compscitech.2018.01.04510.1016/j.compscitech.2018.01.045 ↗
51. Maalihan, R.D., Domalanta, M.R.B., Corrales, A.C.C., Caldona, E.B.: Advances in interfacially engineered surface-functionalized fillers for multifunctional polymer composite coatings. Polym. Compos. 46(7), 5857–5881 (2025). https://doi.org/10.1002/pc.2935810.1002/pc.29358 ↗
52. Zhang, Y., Choi, J.R., Park, S.-J.: Enhancing the heat and load transfer efficiency by optimizing the interface of hexagonal boron nitride/elastomer nanocomposites for thermal management applications. Polymer (2018). https://doi.org/10.1016/j.polymer.2018.03.06710.1016/j.polymer.2018.03.067 ↗
53. Ding, J., Zheng, R., Zhang, Y., Zhang, X., Liu, G., Zheng, K.: The high thermal conductive and flexible boron nitride/silicone rubber composites with segregated structure. Mater. Res. Express 8(3), 035306 (2021). https://doi.org/10.1088/2053-1591/abed6b10.1088/2053-1591/abed6b ↗
54. Fakiridis, S., Hodge, S.A., Karagiannidis, P.G.: Thermal interface materials with hexagonal boron nitride and graphene fillers in PDMS matrix: thermal and mechanical properties. Energies 16(6), 2522 (2023). https://doi.org/10.3390/en1606252210.3390/en16062522 ↗
55. Tiwari, A., Panda, S.K.: Stiffness enhancement of polymer nanocomposites via graphene nanoplatelet orientation. Polym. Eng. Sci. (2024). https://doi.org/10.1002/pen.2663510.1002/pen.26635 ↗
56. Jawaid, M., Sultan, M.T.H., Saba, N. (eds.): Failure analysis in biocomposites, fibre-reinforced composites and hybrid composites. Woodhead Publishing (2018)
57. Alvarez, G.A., Christiansen-Salameh, J., Biswas, A., Puthirath, A.B., Jeong, E., Kwon, J., Lee, J., Gray, T., Vajtai, R., Ajayan, P.M., Tian, Z.: Cross-plane thermal conductivity of h-BN thin films grown by pulsed laser deposition. Applied Physics Letters (2023). https://doi.org/10.1063/5.014950810.1063/5.0149508 ↗
58. Guerra, V., Wan, C., McNally, T.: Thermal conductivity of 2D nano-structured boron nitride (BN) and its composites with polymers. Prog Mater. Sci. 100, 170–186 (2019). https://doi.org/10.1016/j.pmatsci.2018.10.00210.1016/j.pmatsci.2018.10.002 ↗