Effect of polymer crosslinking to the failure behavior of thermoplastic composite remelting interface: Molecular dynamics simulation and experimental verification

The forming interface is the weak link of thermoplastic composite complex structures. To explore the effect of polymer crosslinking on the failure behavior of thermoplastic composite remelting interface using "Preforming + Remelting bonding" process, the all-atom models of different types of interfaces were established, and a molecular dynamics (MD) simulation was conducted on the uniaxial tensile failure process of the remelting interface. The failure behavior of the remelting interface with different preforming processes was tested to verify the correctness of MD simulation, and the influencing mechanism of polymer crosslinking reactions in the preforming stage to the remelting interface properties was clarified. The results showed that the yield stress of the uncrosslinked interface reaches 283.2 MPa and 16.0% and 50.6% higher than that of the unilateral and bilateral crosslinked interfaces respectively. The polymer crosslinking reaction during the preforming stage will reduce the interlaminar bonding performance. The interlaminar shear strength (ILSS) of the uncrosslinked interface is 87.46 MPa and 7.21% and 27.36% higher than that of the unilateral and bilateral crosslinked interface respectively, and only 3.95% lower than that of the non-remelting sample formed by standard process. This research provides a new approach for predicting and analyzing the effect of polymer crosslinking on remelting interface properties of thermoplastic composite using "Preforming + Remelting bonding" process.Highlights The failure behavior of different thermoplastic composite remelting interfaces was studied. MD simulation was conducted on the uniaxial tensile failure process of the remelting interface. The influencing mechanism of polymer crosslinking reactions in the preforming stage to the remelting interface properties was clarified. It is effective to explore the failure mechanism of thermoplastic remelting interface by MD simulation. The influence of polymer crosslinking reaction in the preforming stage on the failure behavior of thermoplastic composite remelting interface was explored through a combination of molecular dynamics (MD) simulation and experimental verification. The MD simulation was conducted on the uniaxial tensile failure process of the remelting interfaces. The remelting bonding experiments with different preforming processes were carried out to verify the correctness of MD simulation. The influencing mechanism of polymer crosslinking reactions on the interface remelting bonding performance was clarified through the interlaminar mechanical performance testing and microstructure observation of interlaminar failure modes. image