Building effective core/shell polymer nanoparticles for epoxy composite toughening based on Hansen solubility parameters

Abstract

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.

Influence of Maleinized Polybutadiene on Adhesive Strength and Toughness of Epoxy Resins

“…Moreover, the improved toughness enhances impact resistance, elongation, and resistance to crack propagation [31]. The T-peel strength of E/C/M (5.6 K, 5 phr) was 190.42 N/25 M, whereas that of E/C/M (5.6 K, 10 phr) showed a slight increase, that is, 195.83 N/25 M. The enhanced T-peel strength imparts excellent physical strength and resistance to vibration, impact, and shock [32]. However, the E/C/M (5.1 K) samples showed slight crack propagation and had a brittle nature after the curing process, which drastically affects the development of first-rate epoxy resin adhesives for practical applications.…”

Controlling Molecular Dye Encapsulation in the Hydrophobic Core of Core–Shell Nanoparticles for In Vivo Imaging

“…There is a solubility parameter (SP), which is defined as the proportion of cohesive energy density as proposed in 1949 [83], that can provide a measure of their affinity between two molecules. SP is a thermodynamic parameter for liquids, but it can be applied to discuss the solubility of solids in a solvent [84][85][86] as well as the compatibility of two solids, such as polymers and carbon nanomaterials [87], or polymer nanoparticles and epoxy resin [88]. Thus, SP can be applied to organic molecules by examining the solubility and turbidity of polymers and powders in solvents with different SP values [89].…”

Study on a novel epoxy‐terminated dendritic modifier as an active toughening agent for epoxy resin

“…17 (3) Nanomaterials. [19][20][21][22][23][24][25][26] Islam et al 19 added nano-CuO and SiO 2 into epoxy resin, which effectively improved the fracture properties of the resin at low temperature. Liu et al 20 added nano-SiO 2 rubber core-shell particles to the resin and improved Young's modulus, tensile strength, fracture toughness and impact strength.…”

“…Interfacial compatibility and dispersion degree are two main influencing factors to nanomaterial toughening epoxy resin. 26,27 Due to the strong van der Waals force between nanomaterials, nanoparticles tend to agglomerate, which leads to a reduction in material properties. 28 At the same time, the process of preparing nanomaterials is complex and costly.…”

“…Their high viscosity causes a significant impact on the resin's processing performance, thus elevating construction difficulty 17 . (3) Nanomaterials 19–26 . Islam et al 19 added nano‐CuO and SiO 2 into epoxy resin, which effectively improved the fracture properties of the resin at low temperature.…”