Molecular dynamics simulation and experimental study on the mechanical properties of PET nanocomposites filled with CaCO3, SiO2, and POE-g-GMA

This work investigated the mechanical properties of polyethylene terephthalate (PET) reinforced with calcium carbonate (CaCO3) and silica (SiO2) nanoparticles, respectively, and the improvement in toughness of the ternary system with the incorporation of graft-modified ethylene-1-octene copolymer (POE-g-GMA). PET nanocomposites were prepared by melt blending extrusion and injection molding. Molecular dynamics (MD) simulation was employed to construct models for binary system filled with nanoparticles and ternary system with the additional inclusion of POE-g-GMA elastomers. The results of mechanical property tests and MD simulation revealed that the binary system exhibited increased elastic modulus and tensile strength, mainly attributed to the effective reinforcement of rigid nanoparticles and the surface adsorption between nanoparticles and the PET matrix enhanced the interfacial interactions. CaCO3 indicated a more pronounced reinforcing effect, possibly due to the higher crystallinity of its composites. The incorporation of POE-g-GMA resulted in a significant improvement in impact strength and the elongation at break of PET nanocomposites. This enhancement in toughness is attributed to the elastomer's ability to absorb a substantial amount of impact energy, while the elastic modulus is higher than that of pure PET.