Thermoplastic polyurethane composites for electromagnetic interference shielding

Year 2024, Volume: 5 Issue: 1, 23 - 36, 30.06.2024

Ümmühan Kaya , Hülya Kaftelen Odabaşı

https://doi.org/10.55212/ijaa.1479997

Abstract

Electromagnetic pollution has been a negative effect of the interest in electronic devices with advancing technology. Therefore, electromagnetic interference (EMI) shielding materials have become important. Although metals are mostly preferred due to their conductive properties, due to their disadvantages such as high density and low corrosion resistance, interest in lightweight, high strength and high corrosion resistance polymers composites has increased. Thermoplastic composites are used in a wide range of applications due to their light weight, easy processing and recyclability.
Based on the principle of electromagnetic interference shielding, many complex factors have been found to have an influential role in achieving the desired shielding efficiency for conductive polymer composites. These include the type, morphology, amount and dispersion of nanoparticles, which greatly affect the conductive properties of conductive polymer composites. Surface conductive layer or high-content metal-filled products provide good electromagnetic interference shielding, mainly through reflection, but they can often lead to high reflection, resulting in strong secondary electromagnetic radiation. Thus, reflection-based EMI shielding can only prevent interference by shielding material, but cannot effectively control and eliminate lost electromagnetic waves. Therefore, eliminating secondary electromagnetic wave pollution can be achieved by adding magnetic nanoparticles and carbon-based (such as carbon fiber) hybrid materials to support the absorption property of conductive polymer composites. Here, magnetic nanoparticles provide magnetic loss while carbon nanofillers contribute to dielectric loss, which can more effectively dissipate electromagnetic waves through absorption. Another important factor affecting the shielding efficiency is the influence of the structural properties of the polymer composites (bulk or 3D porous structure).
Polyurethane thermoplastics are important in terms of EMI shielding because they are flexible, lightweight, economical and can be produced with pore structures in three dimensions. By adding carbon-based materials such as graphene, carbon black, carbon fibre to the polymer matrix, mechanical, electrical conductivity, and thermal properties are improved. Therefore, carbon-based materials can be considered as a potentially effective option for blocking electromagnetic interference in electronic devices.

Keywords

Carbon based filler materials, Electromagnetic interference shielding, Thermoplastic polyurethane

Thanks

Bu çalışma Fırat Üniversitesi Fen Bilimleri Enstitüsü Havacılık Bilim ve Teknolojileri yüksek lisans öğrencisi Ümmühan KAYA’nin yüksek lisans tezinden üretilmiştir.

Elektromanyetik girişim koruması için termoplastik poliüretan kompozitler

Abstract

Gelişen teknoloji ile birlikte elektronik cihazlara olan ilginin olumsuz bir etkisi elektromanyetik kirlilik olmuştur. Bu yüzden elektromanyetik girişim (EMI) kalkanlama malzemeleri önemli hale gelmiştir. Yüksek yoğunluklu ve düşük korozyon direncine sahip metaller çoğunlukla iletkenlik özellikleri nedeni ile tercih edilse de bu dezavantajlarından dolayı, hafif, yüksek mukavemet ve yüksek korozyon direncine sahip polimerler kompozitlere ilgi artmıştır. Termoplastik kompozitler hafif, kolay işlenebilir ve geri dönüştürülebilir olmaları nedeni ile geniş bir uygulama alanlarında kullanılmaktadır. Elektromanyetik girişim kalkanlama prensibine dayalı olarak, birçok karmaşık faktör, iletken polimer kompozitler için istenen kalkanlama verimini elde etmede etkili bir role sahip olduğu görülmüştür. Bunlar, iletken polimer kompozitlerin iletkenlik özelliklerini büyük ölçüde etkileyen nanopartiküllerin türü, morfolojisi, miktarı ve dağılımını içerir. Yüzey iletken tabakası veya yüksek içerikli metal dolgulu ürünler, esas olarak yansıma yoluyla iyi elektromanyetik girişim koruması sağlar, ancak genellikle yüksek yansımaya yol açarak güçlü ikincil elektromanyetik radyasyona neden olabilirler. Dolayısı ile yansıma tabanlı EMI koruma, yalnızca kalkanlama malzemesiyle girişimi önleyebilir, ancak kayıp elektromanyetik dalgaları etkili bir şekilde kontrol edemez ve ortadan kaldıramaz. Bu nedenle, ikincil elektromanyetik dalga kirliliğini ortadan kaldırmak manyetik nanopartiküller ile karbon esaslı (karbon fiber gibi) hibrit malzemelerinin iletken polimer kompozitlerin absorpsiyon özelliğini desteklemek için ilave edilmesi ile sağlanabilir. Burada, manyetik nanoparçacıklar manyetik kayıp sağlarken karbon nano dolgu maddeleri, soğurma yoluyla elektromanyetik dalgaları daha etkili bir şekilde dağıtabilen dielektrik kaybına katkıda bulunur. Kalkanlama verimini etkileyen bir diğer önemli faktör ise, polimer kompozitlerin yapısal özelliklerinin (yığın veya 3 boyutlu gözenekli yapıya sahip olması) etkisidir.
Poliüretan termoplastikler, esnek, hafif, ekonomik olmaları ve üç boyutta gözenek yapılı şekilde üretilebilmeleri nedeniyle EMI koruması açısından önemlidir. Grafen, karbon siyahı, karbon fiber gibi karbon esaslı malzemelerin polimer matrisine ilave edilmesi ile mekanik, elektriksel iletkenlik ve termal özelliklerinde iyileşme sağlanır. Bu nedenle, karbon esaslı malzemeler, elektronik cihazlarda elektromanyetik girişimi engellemek için potansiyel olarak etkili bir seçenek olarak kabul edilebilir.

Keywords

Elektromanyetik girişim kalkanlama, Karbon esaslı dolgu malzemeleri, Termoplastik poliüretan

Thanks

Bu çalışma Fırat Üniversitesi Fen Bilimleri Enstitüsü Havacılık Bilim ve Teknolojileri yüksek lisans öğrencisi Ümmühan KAYA’nin yüksek lisans tezinden üretilmiştir.

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