All‐Organic Filler with Fractal Structure for Reinforcement and Toughening of Aromatic Polyamide Film

Abstract

The simultaneous enhancement in strength and toughness seems to be an intrinsic contradiction in multiple material designs, including the structural regulation of polymer composites. In this study, benzimidazole-containing aromatic-polyamide thin films are used as typical rigid polymers with high strength and modulus to study their strength-toughness collaboration via a multi-scaled stress distribution mechanism. A fully organic deformable filler with a fractal structure is designed. Utilizing the large-scale deformability of the filler to absorb the energy and dislocation node structure of the filler to disperse the stress, the composite thin film is significantly toughened, which is reflected in the elongation at break increased by 144.9% and energy at break increased by 154.2%. In addition, the specific fractal structure of the filler provided a larger interaction area, which enhanced the interfacial bonding force and improved the strength of the film. Moreover, owing to the larger interaction area provided by the fractal structure, the interface bonding force between the filler and matrix due to the similar chemical structures is further improved and the tensile strength of the composite thin film is increased from 389.2 ± 11.98 to 426.2 ± 4.41 MPa.