Tensile, flexural, and mode-I cracking behavior of interpenetrating phase composites (IPC), developed using additively manufactured PLA-based structures with different infill densities and epoxy resin polymer as matrix

Abstract

Interpenetrating phase composites (IPC) materials are designed to combine the advantages of made-from materials or develop an intended behavior. Recently, the use of 3D printed structures has received attention due to advantages, such as the rapid and cheap prototyping techniques of complex structures. However, most materials, such as polylactic acid (PLA) used for conventional 3D printing, have low strength and insignificant durability. To overcome these issues, the excellent characteristics of polymer adhesives, such as epoxy resin, can be used to increase their strength and durability. In this paper, PLA-based 3D printed samples and epoxy resin adhesive were merged to develop an interpenetrating phase composite. The samples were printed with 25, 50, 75, and 100 infill percentages and tested in direct tensile, bending, and mode-I fracture. From the results, it can be seen that reducing the infill percentage to 75, 50, and 25 % reduces the tensile strength to 16, 9, and 3 MPa (−40 %, −66 %, and −90 % compared to the sample with 100 % infill with 26 MPa strength), adding epoxy resin to develop an IPC, results in 24, 29 and 32 MPa tensile strength. Compared to 3D-printed parts with the same infill percentages, the IPCs have 150, 320, and 1140 % higher tensile strengths, respectively. Also, the failed samples were reviewed by scanning electron microscope.