The effect of inorganic particles on the breakdown strength and mechanical properties of EVA‐based composites

Abstract

Ethylene-vinyl acetate (EVA) copolymer was melt-blended with different inorganic particles, such as alumina trihydrate (ATH), montmorillonite-based organoclay (CLO15A) and organophilic silica (R202) to produce (nano)composites with outstanding electrical breakdown strength. The composites loaded with different amount of particles were characterized by dielectric, rheological, morphological and mechanical properties. The addition of the particles resulted in an increase of electrical breakdown strength, whose results depend on the nature and amount of filler. The addition of 1%-5% of ATH resulted in an increase of 50% of this property. Similar results were observed for the composites loaded with 7% of CLO15A and R202. All composites displayed low values of dielectric constant and dielectric loss, which is interesting for insulator applications. The presence of the filler did not exert great influence on the rheological properties of the composites, thus keeping the good processability of EVA matrix. Finally, the composites containing the organoclay presented the best mechanical response.

Nanobrick Wall Multilayer Thin Films with High Dielectric Breakdown Strength

“…The dual clay nanocomposite has nearly double the breakdown strength (249 kV/mm) when compared to the single clay nanocomposite, which is believed to be a result of the significantly higher inorganic loading and the influence of a more tortuous pathway for charge transport. Having a high loading of inorganic material in polymer nanocomposites has been shown to greatly increase breakdown strength. , It is important to note that some reports do show that breakdown strength can decrease as inorganic loading increases, but this typically occurs due to nanocomposite preparation techniques leading to more defects (e.g., filler aggregation or charge transport pathways), which can negatively impact breakdown strength. , The dielectric properties of the analyzed systems are shown in Figure .…”

“… 41 , 42 It is important to note that some reports do show that breakdown strength can decrease as inorganic loading increases, but this typically occurs due to nanocomposite preparation techniques leading to more defects (e.g., filler aggregation or charge transport pathways), which can negatively impact breakdown strength. 43 , 44 The dielectric properties of the analyzed systems are shown in Figure 3 .…”