Evolution of Charge Trapping and Insulating Performances of Epoxy Materials Containing Hydrolyzable Chlorine During Hygrothermal Aging

Abstract

Hydrolyzable chlorine is a well-known residue issued from the synthesis of epoxy resin, which may impart specific dielectric properties. In this work, the changes in distributed energy levels and charge trap depths of the molecule containing such defects are investigated using quantum chemical calculations. These changes are analyzed from the microscopic perspectives of electron energy structure and electron cloud offset. The charge transport and charge injection behavior in epoxy materials before and after the hydrolysis are predicted using the analysis results. The volume resistivities and space charges of epoxy materials with three different hydrolyzable chlorine contents are tested at different hygrothermal aging times, which are consistent with the previous predictions. These results are used to explain the AC breakdown strength of these epoxy materials at different hygrothermal aging times. It is indicated that the structural changes (electronegativity and atomic position changes) of the molecule containing hydrolyzable chlorine before and after hydrolysis change the spatial distribution of electron cloud density between and on valence bonds, and in turn change the energy levels of different molecular segments. This results in a large increase in the overall electron trap depth and a small decrease in the overall hole trap depth of the molecule after hydrolysis.

Preparation of an Electronic-Grade Cardol-Based Epoxy Reactive Diluent By Stepwise Dichlorination

“…Currently, the hydrolyzable chlorine content of commercially available Cardanol-based reactive diluents is generally above 6000 ppm. When used in electronic packaging, the presence of hydrolyzable chlorine can cause corrosion of components such as copper, which will greatly reduce the safety and service life of electronic devices. , This is one of the key issues limiting the application of Cardanol-based reactive diluents in high-end fields such as electronic packaging.…”

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

“…9 Traditional glycidyl ether-based epoxy resins, like DGEBA, are typically synthesized by reacting with epichlorohydrin, resulting in residual chlorine content. 10,11 Notably, hydrolyzable chlorine residues can significantly influence the performance of the cured resin. 10 Conversely, cycloaliphatic epoxy resins, synthesized through peroxidemediated oxidation of double bonds, exhibit no chlorine residue.…”

“…10,11 Notably, hydrolyzable chlorine residues can significantly influence the performance of the cured resin. 10 Conversely, cycloaliphatic epoxy resins, synthesized through peroxidemediated oxidation of double bonds, exhibit no chlorine residue. 12 Moreover, these cycloaliphatic resins demonstrate excellent processability, with cured resins exhibiting high glass transition temperatures, superior resistance to UV radiation, and impressive mechanical and dielectric properties.…”

“…Thermosetting resins typically exhibit outstanding mechanical properties and commendable chemical resistance and dimensional and thermal stabilities, among other desirable characteristics. − Epoxy resins hold a prominent position in thermosets as they are broadly employed in coatings, adhesives, and composites. , The low cost, uncomplicated processing, and suitability for mass automated production have established epoxy resins as a dominant player in the integrated circuits packaging industry . Traditional glycidyl ether-based epoxy resins, like DGEBA, are typically synthesized by reacting with epichlorohydrin, resulting in residual chlorine content. , Notably, hydrolyzable chlorine residues can significantly influence the performance of the cured resin . Conversely, cycloaliphatic epoxy resins, synthesized through peroxide-mediated oxidation of double bonds, exhibit no chlorine residue .…”