Recycled Polypropylene/Strontium Ferrite Polymer Composite Materials with Electromagnetic Shielding Properties

Alina Ruxandra Caramitu; Magdalena Valentina Lungu; Romeo Cristian Ciobanu; Ioana Ion; Mihai Marin; Virgil Marinescu; Jana Pintea; Sebastian Aradoaei; Oliver Daniel Schreiner

doi:10.3390/polym16081129

Recycled Polypropylene/Strontium Ferrite Polymer Composite Materials with Electromagnetic Shielding Properties

Polymers (Basel). 2024 Apr 17;16(8):1129. doi: 10.3390/polym16081129.

Authors

Alina Ruxandra Caramitu¹, Magdalena Valentina Lungu¹, Romeo Cristian Ciobanu², Ioana Ion¹, Mihai Marin¹, Virgil Marinescu¹, Jana Pintea¹, Sebastian Aradoaei², Oliver Daniel Schreiner²

Affiliations

¹ National Institute for Research and Development in Electrical Engineering ICPE-CA Bucharest, 030138 Bucharest, Romania.
² Department of Electrical Measurements and Materials, Gheorghe Asachi Technical University, 700050 Iasi, Romania.

Abstract

This paper presents the obtaining and characterization of recycled polypropylene/strontium ferrite (PP/SrFe₁₂O₁₉) polymer composite materials with applications in the electromagnetic shielding of vehicle interiors (mainly automotive electronics-carcasses) from the electromagnetic radiation emitted mainly by exterior sources-electrical lines and supply sources-in terms of the development of the new electrical vehicles. With this aim, suitable polymer composite materials were developed using SrFe₁₂O₁₉ filler in two forms (powder and concentrate). The recycled PP polymer and composite materials with a PP/SrFe₁₂O₁₉ weight ratio of 75/25 and 70/30 were obtained in two stages, i.e., pellets by extrusion and samples for testing through a melt injection process. The characterization of the obtained materials took into account the requirements imposed by the desired applications. It consisted of determining the mechanical and dielectric properties, and microstructure analyses, along with the determination of the resistance to the action of a temperature of 70 °C, which is higher than the temperatures created during the summer inside vehicles. The performance of these materials as electromagnetic shields was assessed through functional tests consisting of the determination of magnetic permeability and the estimation of the electromagnetic shielding efficiency (SE). The obtained results confirmed the improvement of the mechanical, dielectric, and magnetic properties of the PP/SrFe₁₂O₁₉ composites compared to the selected PP polymers. It is also found that all the composite materials exhibited reflective shielding properties (SE_R from -71.5 dB to -56.7 dB), with very little absorption shielding. The most performant material was the composite made of PP/SrFe₁₂O₁₉ powder with a weight ratio of 70/30. The promising results recommend this composite material for potential use in automotive shielding applications against electromagnetic pollution.

Keywords: PP/SrFe12O19; electromagnetic radiation; magnetic permeability; polymer composite; polypropylene/strontium ferrite; reflection shielding.

Grants and funding

This work was supported by a publication grant from the Technical University of Iasi, and it was based on the joint experimental research of participating organizations, partially financed on the part of the National Institute for Research and Development in Electrical Engineering ICPE-CA Bucharest by the Romanian Ministry of Research, Innovation and Digitalization, project number 25PFE/30.12.2021—Increasing R-D-I capacity for electrical engineering-specific materials and equipment with reference to electromobility and “green” technologies within PNCDI III, Programme 1.