Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE ABSTRACT
A novel active-inert chain-enveloping strategy was developed to enhance the toughness of epoxy resins by blending phenolphthalein-based poly(arylether sulfone) (PPES) with carboxyl-functionalized PPES (PPES-C). The resulting composite toughening agent, PESP-C, improves the properties of epoxy resins through chain entanglement and chemical crosslinking, forming a robust interfacial network. The flexible long-chain segments of PPES-C and the rigid PPES chains form a stable 3D network, enabling dynamic energy dissipation. Thermogravimetric and DSC analyses showed that T
d5% > 370°C and T
g = 135°C, indicating enhanced thermal stability and good compatibility. SEM confirmed the uniform dispersion of PESP-C in the resin. With 10 wt% PESP-C, the impact strength increased by 76.7%, reaching 23.5 kJ m−2, and the fracture elongation increased by 81.0%, reaching 3.8, while the tensile strength remained high. Furthermore, free volume simulations and toughening mechanisms were studied, providing an optimized framework for efficient epoxy resin toughening.