Improvement of Interfacial Bonding Force between PMI Foam and CFRP in PMI Foam-Cored CFRP Sandwich Composites

In the polymethacrylimide (PMI) foam-cored carbon fiber reinforced polymer (CFRP) sandwich composite, PMI foam is the core material and CFRP is the surface material. The interfacial bonding force between the foam core and the skin layer is an important factor that determines the mechanical properties of the foam-cored sandwich composite. This study improved the interfacial bonding force between the PMI foam core and the CFRP skin layer in the PMI foam-cored sandwich CFRP composite. This was achieved by fabricating holes of a constant volume on the surface of the PMI foam; in addition, an epoxy, the matrix of CFRP, was filled to increase the bonding area of the interface between the PMI foam and the CFRP skin layer. Then by processing holes with constant distance, it was confirmed that the interfacial bonding force according to the intervals of the holes. As a result, the interfacial bonding force of samples with holes increased on average up to 63.5 % compared with the samples without the processed holes.