Study on the Effect of Adding Nano-Sio2 on the Interfacial Properties of 3D Printed Continuous Carbon Fiber/PLA Composites

Abstract

This study systematically examines the influence of nano-silica content on the interface properties of continuous /PLA carbon fiber composites and its basic mechanism. PLA composite filaments with different nano-SiO2_2 content were prepared by gradient experiment, and short beam shear test samples were made by continuous fiber 3D printing technology. By combining interlaminar shear strength test (ILSS) and fracture characteristic scanning electron microscope (SEM), the relationship between property change and microstructure was analyzed. The results show that adding nano-SiO2_2 can significantly improve ILSS, but the strengthening effect depends on the concentration. The best reinforcement is obtained with the amount of nano-SiO2_2 between 1.0 wt% and 1.5 wt%. If more is added, the performance will be degraded because the particles are aggregated and cannot be well wetted. Microscopic analysis shows that a large amount of nano-SiO2_2 is uniformly dispersed in the interface region. This improves the mechanical bonding between the matrix and the fiber, and contributes to the transition from brittle fracture to flexible fracture at the interface. This study provides empirical evidence to improve the interface characteristics of continuous 3D printing carbon fiber composites by nano-modification of matrix.