The dispersion state of fillers in the polymer matrix is an important factor to determine the properties of the polymer composites. Here, a new method for the accurate quantitative evaluation dispersion state of fillers through three‐dimensional (3D) visualization and fractal analysis is reported. First of all, the data model of the dispersed state of the fillers is obtained through 3D visualization techniques. Then the fractal dimensions of different samples are obtained by software based on the fractal theory. As the filler increases, the fractal dimension is firstly decreases to a minimum and then increases. Under this extreme point condition, the theoretical dispersion state of the fillers is uniform. The accurate quantitative description of the dispersion state provides a new basis for establishing the relationship between the dispersion state and the mechanical properties of the fillers in various composites.

No abstract

Silicone rubber is widely used in industry, dairy products, medical, defense support, and other fields due to its excellent comprehensive properties, which have become one of the most important research objects of high-performance elastomer. Cationic-π dynamic noncovalent bond has attracted more and more attention from material researchers due to its dynamic reversibility and design flexibility and has been applied to different material systems, giving new characteristics to traditional materials. Cationic-π/covalently crosslinked silicone rubber was prepared by one-step method with glycidol propyl terminated polydimethylsiloxane (DMS-E21) as basic polymer, epoxy indole monomer (IN) as crosslinking structure modifier, Europium ion (Eu 3+ ) as cation donor and triethylenetetramine (TETA) as a crosslinking agent. The influence of the reversibility of Eu 3+ -π interaction on the static and dynamic mechanical behaviors of silicone rubber was studied. The results show that the elongation at break of cationic-π/covalent hybrid crosslinked silicone rubber increases by more than 60% compared with pure covalent crosslinked silicone rubber when the breaking energy reaches the maximum, while the tensile strength increases by more than 100% and the introduction of Eu 3+ -π dynamic bond can weaken the Mullins effect and the Payne effect on the high temperature of silicone rubber with obvious creep resistance. It shows an excellent mechanical strengthening effect with the characteristic of strengthening and toughening simultaneously and attractive nonlinear mechanical behavior on elastomers.cation-π, mechanical properties, Mullins effect, non-covalent bond, silicone rubber | INTRODUCTIONSilicone rubber is considered an important strategic material because of its superior high and low-temperature adaptability, aging resistance, radiation resistance, and other properties, and occupies an irreplaceable position in aerospace, machinery, medical, and other fields. [1][2][3][4] Polymer materials have typical viscoelastic properties. [5] Understanding the mechanical behavior of silicone rubber is of great significance to guide its application. The mechanical behavior of silicone rubber has now been studied in depth in terms of inorganic nanofiller filling, [6,7] rubberplastic blending, [8,9] molecular chain structure design [10,11] and cross-linked network structure design, [12,13] and a series Xuejun Yue and Shangjun Zeng are co-first authors of the article.