Processing and fracture behavior of a polyethylene-based thermoplastic adhesive and a glass-fiber filled epoxy adhesive

The processing and fracture performance of a high-density polyethylene (HDPE)-based thermoplastic adhesive and an epoxy-based thermosetting adhesive with a glass fiber additive were studied. Differential scanning calorimetry (DSC) was used to characterize the processing parameters. Double cantilever beam (DCB) fracture testing and butt-joint tensile testing were used to characterize the adhesive joint fracture toughness and strength. Although the thermoplastic adhesive had low strength, it exhibited high DCB fracture toughness because of a large plastic deformation zone in the fracture process. The fiber additive in the thermosetting adhesive stabilized the DCB fracture. Loading speed, adhesive thickness, pre-crack length, and curing temperature were all considered in the study.