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Vitrmers are a new type of functional resins having the majority of published studies focused on reprocessing, recycling, healing, welding, and shape memory, and their mechanical properties are extensively investigated. While most of the intended applications of these vitrimers are related to elastomers and composites, little research has been published on their dielectric properties and their applications in tele‐communication fields. Herein, dielectric property of four typical epoxy‐anhydride vitrimers were investigated. Vitrimer catalyzed by Zn(Acac)2 (zinc acetylacetonate) show excellent re‐processability, which were further improved by introducing MTHPA (methyl terahydrophthalic anhydride) and styrene maleic anhydride (SMA) polymers. The modified epoxy vitrimer shows favorable Tg of 106°C and low dielectric constant (2.77 at 10 GHz). Notably, the modified vitrimer are still re‐processable and degradable due to the dynamic ester bonds, and maintains its dielectric and thermal performances after being reprocessed.

Particles have been demonstrated to toughen epoxy resins, especially for fiber-reinforced epoxy composites, and core/shell particles are one of them. It is known that not all particles toughen the same but most evaluations are through experimentation, and few studies have been conducted to accurately predict the particles’ toughening effect or guide the design of effective particles. In this study, efforts were made to find the control factors of core/shell particles, primarily interfacial compatibility and degree of dispersion, and how to predict them. Nanocomposites were fabricated by incorporating core/shell nanoparticles having various shell polymer compositions, especially their polarities. Their compatibility was estimated using a novel quantitative approach via adopting the theory of Hansen solubility parameters (HSP), in which the HSP of core/shell nanoparticles and the epoxy matrix were experimentally determined and compared. It was found that the HSP distance was a good predictor for particle dispersion and interfacial interaction. Particles having a small HSP distance (R a) to the epoxy resin, represented by the polybutylacrylate core/polymethyl methacrylate shell particle having the smallest R a of 0.50, indicated a uniform dispersion and strong interfacial bonding with the matrix and yielded outstanding toughening performance. In contrast, polybutylacrylate core/polyacrylonitrile shell particle having the largest HSP distance (6.56) formed aggregates and exhibited low interfacial interaction, leading to poor toughness. It was also demonstrated that HSP can provide an effective strategy to facilitate the design of effective core/shell nanoparticles for epoxy toughening.