Investigation of mechanical and EMI shielding performance of polypropylene/carbon nanotube/glass fiber microcellular foam

Document Type : UFGNSM Conference


1 Physics and Chemistry Group, Faculty of basic sciences, Imam Ali University, Tehran, Iran; Nanomaterials Group, Department of Materials Engineering, Tarbiat Modares University, Tehran, Iran

2 Department of Polymer Engineering & Color Technology, AmirKabir University of Technology, Tehran, Iran


Polypropylene (PP)/Carbon-Nanotube (CNT) nanocomposites and PP/CNT/Glass fiber (GF) hybrids were foamed using supercritical carbon dioxide (CO2) through a batch foaming process. Uniform nanofiller dispersion was assessed by field emission scanning electron microscopy (FE-SEM). By incorporating CNTs in the matrix, the average cell size was reduced to less than one-second that of neat foam (from 49 to 22.5 µm), and cell density increased. As a matter of fact, high electrical conductivity is crucial to achieving a great electromagnetic interference (EMI) shielding performance. Hence, CNTs were loaded up to 3 wt%. By incorporation of CNTs, electrical conductivity increased from ~10-16 to ~10-4 and ~10-5 S/cm for unfoamed and foamed PP/CNT3 samples, respectively, and EMI shielding effectiveness increased to 11 dB and 9.5 dB for unfoamed and foamed PP/CNT3 samples, respectively. After evaluating the microstructural and electrical properties of the nanocomposites and their foams, as well as elucidating the foaming process's role in the EMI shielding performance of the hybrids and foams, there was a great need to investigate the mechanical properties of hybrid systems and the effect of fiber concentration. Tensile properties revealed that by increasing the fiber content, young modulus and tensile strength increased for unfoamed samples and decreased for foams. The compression test of hybrid foams showed that by loading nanotubes and glass fibers, compressive mechanical properties increased. Also, by adding CNTs and glass fibers, impact properties increased and decreased, respectively, for solid and foamed hybrids. Moreover, by loading both additives impact properties enhanced.



    1. Mohebbi A, Mighri F, Ajji A, Rodrigue D. Current Issues and Challenges in Polypropylene Foaming: A Review. Cellular Polymers. 2015;34(6):299-338.
    2. Martínez AB, Realinho V, Antunes M, Maspoch ML, Velasco JI. Microcellular Foaming of Layered Double Hydroxide−Polymer Nanocomposites. Industrial & Engineering Chemistry Research. 2011;50(9):5239-47.
    3. Jun Y-s, Habibpour S, Hamidinejad M, Park MG, Ahn W, Yu A, et al. Enhanced electrical and mechanical properties of graphene nano-ribbon/thermoplastic polyurethane composites. Carbon. 2021;174:305-16.
    4. Tran M-P, Detrembleur C, Alexandre M, Jerome C, Thomassin J-M. The influence of foam morphology of multi-walled carbon nanotubes/poly(methyl methacrylate) nanocomposites on electrical conductivity. Polymer. 2013;54(13):3261-70.
    5. Zhao B, Wang R, Li Y, Ren Y, Li X, Guo X, et al. Dependence of electromagnetic interference shielding ability of conductive polymer composite foams with hydrophobic properties on cellular structure. Journal of Materials Chemistry C. 2020;8(22):7401-10.
    6. Che RC, Peng LM, Duan XF, Chen Q, Liang XL. Microwave Absorption Enhancement and Complex Permittivity and Permeability of Fe Encapsulated within Carbon Nanotubes. Advanced Materials. 2004;16(5):401-5.
    7. Zakiyan SE, Azizi H, Ghasemi I. Effect of cell morphology on electrical properties and electromagnetic interference shielding of graphene-poly(methyl methacrylate) microcellular foams. Composites Science and Technology. 2018;157:217-27.
    8. Panahi-Sarmad M, Noroozi M, Abrisham M, Eghbalinia S, Teimoury F, Bahramian AR, et al. A Comprehensive Review on Carbon-Based Polymer Nanocomposite Foams as Electromagnetic Interference Shields and Piezoresistive Sensors. ACS Applied Electronic Materials. 2020;2(8):2318-50.
    9. Aghvami‐Panah M, Jamalpour S, Ghaffarian SR. Microwave‐assisted foaming of polystyrene filled with carbon black; effect of filler content on foamability. SPE Polymers. 2021;2(1):86-94.
    10. Yang Y, Gupta MC, Dudley KL, Lawrence RW. Conductive Carbon Nanofiber-Polymer Foam Structures. Advanced Materials. 2005;17(16):1999-2003.
    11. Zhang H-B, Yan Q, Zheng W-G, He Z, Yu Z-Z. Tough Graphene−Polymer Microcellular Foams for Electromagnetic Interference Shielding. ACS Applied Materials & Interfaces. 2011;3(3):918-24.
    12. Zhu J, Wei S, Haldolaarachchige N, Young DP, Guo Z. Electromagnetic Field Shielding Polyurethane Nanocomposites Reinforced with Core–Shell Fe–Silica Nanoparticles. The Journal of Physical Chemistry C. 2011;115(31):15304-10.
    13. Zhao B, Hamidinejad M, Wang S, Bai P, Che R, Zhang R, et al. Advances in electromagnetic shielding properties of composite foams. Journal of Materials Chemistry A. 2021;9(14):8896-949.
    14. Biswas S, Panja SS, Bose S. Tailored distribution of nanoparticles in bi-phasic polymeric blends as emerging materials for suppressing electromagnetic radiation: challenges and prospects. Journal of Materials Chemistry C. 2018;6(13):3120-42.
    15. Zhao B, Shao G, Fan B, Zhao W, Xie Y, Zhang R. Synthesis of flower-like CuS hollow microspheres based on nanoflakes self-assembly and their microwave absorption properties. Journal of Materials Chemistry A. 2015;3(19):10345-52.
    16. Zhao B, Li Y, Zeng Q, Wang L, Ding J, Zhang R, et al. Galvanic Replacement Reaction Involving Core–Shell Magnetic Chains and Orientation‐Tunable Microwave Absorption Properties. Small. 2020;16(40):2003502.
    17. Wang G, Zhang D, Wan G, Li B, Zhao G. Glass fiber reinforced PLA composite with enhanced mechanical properties, thermal behavior, and foaming ability. Polymer. 2019;181:121803.
    18. Asoodeh F, Aghvami-Panah M, Salimian S, Naeimirad M, khoshnevis H, Zadhoush A. The Effect of Fibers’ Length Distribution and Concentration on Rheological and Mechanical Properties of Glass Fiber–Reinforced Polypropylene Composite. Journal of Industrial Textiles. 2021:152808372110432.
    19. Aghvami-Panah M, Panahi-Sarmad M, Seraji AA, Jamalpour S, Ghaffarian SR, Park CB. LDPE/MWCNT and LDPE/MWCNT/UHMWPE self-reinforced fiber-composite foams prepared via supercritical CO2: A microstructure-engineering property perspective. The Journal of Supercritical Fluids. 2021;174:105248.
    20. Jamalpour S, Ghaffarian SR, Goldansaz H, Jangizehi A. Improving microcellular foamability of amorphous supramolecular polymers via functionalized nanosilica particles. Polymer Composites. 2019;40(1):364-78.
    21. Miller D, Kumar V. Microcellular and nanocellular solid-state polyetherimide (PEI) foams using sub-critical carbon dioxide II. Tensile and impact properties. Polymer. 2011;52(13):2910-9.
    22. Ameli A, Nofar M, Park CB, Pötschke P, Rizvi G. Polypropylene/carbon nanotube nano/microcellular structures with high dielectric permittivity, low dielectric loss, and low percolation threshold. Carbon. 2014;71:206-17.
    23. Wan F, Tran MP, Leblanc C, Béchet E, Plougonven E, Léonard A, et al. Experimental and computational micro-mechanical investigations of compressive properties of polypropylene/multi-walled carbon nanotubes nanocomposite foams. Mechanics of Materials. 2015;91:95-118.