A Brief Overview on Epoxies in Electronics: Properties, Applications, and Modifications

Abstract

This paper offers a short overview of epoxy resins, encompassing their diverse characteristics, variants, chemical modifications, curing processes, and intriguing electrical properties. Epoxies, valued for their multifunctional attributes, serve as fundamental materials across industries. In the realm of dielectric strength, epoxy resins play a crucial role in electrical insulation. This paper discusses the mechanisms governing dielectric breakdown, strategies to enhance dielectric strength, and the impact of various fillers and additives on insulation performance. Through an exploration of recent research and advancements, this paper delves into the spectrum of epoxy properties, the array of subspecies and variants, their chemical adaptability, and the intricacies of curing. The examination of electrical resistance and conductivity, with a focus on their frequency-dependent behavior, forms a pivotal aspect of the discussion. By shedding light on these dimensions, this review provides a concise yet holistic understanding of epoxies and their role in shaping modern materials science.

Keywords: chemical modifications; curing; dielectric strength; electrical conductivity; epoxy resins; thermal conductivity.

Figure 1

Illustration of the formation process of a polymer with a three-dimensional structure. (Figure from [24], permission granted by “Elsevier”).

Figure 2

Histogram depicting the breakdown strength of RIP with varying nanoparticle constituents [65].

Figure 3

Temperature-dependent spectral properties of epoxy resin with varying proportions of hydroxyl-terminated liquid nitrile rubber (HTBN) at a frequency of 50 Hz: (a) relative permittivity; (b) dielectric loss factor [66].

Figure 4

Dependences of thermal conductivity on temperature for materials 1—ED20; 2—ED20 + IrSiO₄ + TBT; 3—ED + IrSiO₄; 4—ED + Al₂O₃ + TBT; 5—ED20 + Al₂O₃ [78].

Figure 5

(a) Change in current at a constant voltage after adding a hardener (t = 0) for different concentrations of CNTs; (b) specific conductivity (σ) of the epoxy matrix at various mass concentrations (n) of CNTs; 1—samples through which current was passed during polymerization; 2—current was not passed [80].

Figure 6

Dependence of dielectric constant (a,c) and the dielectric loss tangent (b,d) on frequency for various samples: uncharged sample (1), corona (2), and thermoelectric (3) based on ED-20 epoxy resin cured with PEPA in a stoichiometric ratio, and thermoelectrics based on epoxy resin ED-20, cured with PEPA (1), L-20 (2), and containing 5% wt. PEF-3A, when curing PEPA (3) [83].

Figure 7

The impact of fluorination on the dispersion of MMT and MWCNTs within epoxy resin. (Figure from [85], permission granted by “Elsevier”).

Figure 8

Dependence of ε′, ε″, and σ of epoxy nanocomposites on the concentration of fillers. (a) ε′; (b) ε″; (c) σ_dc. (Figure from [87], permission granted by “AIP Publishing”).

Figure 9

Frequency dependence of the specific conductivity of the epoxy nanocomposite on the concentration of the filler and the method of orientation in the field of direct (DC) and alternating (AC) currents. (Figure from [88], permission granted by “Elsevier”).

Figure 10

(a) Standard curves depicting flexural stress–displacement relationships, (b) the associated flexural strength, and (c) the flexural modulus for various nanocomposites [92].