3D Printing of Thermally Curable Resin/Continuous Carbon Fiber Composites with Interpenetrating Polymer Interlayer

Abstract

3D printing of continuous carbon fiber composites has been a popular research focus in recent years, since it enables the design freedom and the tuning of structural properties. Currently, the existing 3D printing methods of composites with thermoplastics and photocurable resins lack comparable mechanical performances to the thermally curable thermoset resins. But the thermally curable thermoset resin as a matrix is also limited in the long thermal curing time and the difficulty in maintaining structures without mold or high pressure. In this work, we proposed our own 3D printing strategy of the thermally curable thermoset resin based continuous carbon fiber composites, which is capable of producing rapidly and maintaining the geometrical stability. It is achieved by coating dual-cure resin on the surfaces of the fiber/resin laminates during 3D printing, and forming the interpenetrating polymer network (IPN) at interlayers between the laminates after post-thermal treatment. This strategy was demonstrated in our self-developed robotic-based 3D printer, which contains the functions of thermoset resin impregnation, dual-cure resin coating, and compaction. The current level of mechanical properties of the printed composites has achieved tensile strength of 1132.69 MPa, flexural strength of 1080.37 MPa, and interlaminar shear strength of 48.75 MPa.