Dual Nanofillers-Reinforced Noncovalently Cross-Linked Polymeric Composites with Unprecedented Mechanical Strength

Abstract

Noncovalently cross-linked polymer materials through healing, recycling, and reprocessing can reduce materials consumption and alleviate environmental pollution. However, it remains a huge challenge to fabricate super-strong noncovalently cross-linked polymer materials with mechanical strength comparable to high-performance engineering polymers. Herein, healable and reprocessable noncovalently cross-linked polymer composites with an unprecedented mechanical strength are fabricated by complexation of polyacrylic acid (PAA), polyvinylpyrrolidone (PVPON), and carbonized polymer dots (CPDs) (denoted as PAA-PVPON-CPDs). The incorporation of 15 wt % CPDs generates PAA-PVPON-CPDs composites with a tensile strength of ∼158 MPa and Young’s modulus of ∼8.2 GPa. Serving as nanofillers, the CPDs can establish strong interactions with polymers in PAA-PVPON composites. The CPDs and the in situ-formed PAAPVPON nanoparticles work in concert to significantly strengthen the PAA-PVPON-CPDs composites to an unprecedented strength. The PAA-PVPON-CPDs composites exhibit excellent impact resistance and damage tolerance because of the high mechanical strength of the composites and the energy dissipation mechanism of the CPDs and PAA-PVPON nanoparticles. Moreover, the fractured PAA-PVPON-CPDs composites can be healed to restore their original mechanical strength.