PMI (polymethacrylimide) foam is the latest material in […]
PMI (polymethacrylimide) foam is the latest material in the development of polymer foam core materials. It has low density, excellent high temperature resistance, low dielectric constant and dielectric loss, good fatigue resistance and voltage withstand strength. It has many advantages such as high specific strength and thus has been widely used in core materials of composite sandwich structures, and is widely used in high-speed trains, ships and aerospace.
Limited by the size and shape of the finished PMI foam material, splicing and filling reinforcement of the PMI foam material is inevitable during the overall molding process of the sandwich structure. The existing foaming adhesive material for honeycomb reinforcement  can meet the requirements of low density, high temperature resistance and high strength, but still can not meet the process requirements of PMI foam material at room temperature splicing and setting; existing low density paste adhesive Although the material  satisfies the process requirements of PMI foam material at room temperature splicing and setting, it cannot realize the molding process co-cured with the composite prepreg skin, and its heat resistance can not meet the design requirements.
In this study, cycloaliphatic amines/aromatic amines were used as curing curing agents. The prepared low-density paste adhesives have the advantages of curing at room temperature, curing at medium temperature and high temperature, and fully satisfying EP prepreg-PMI. Process requirements for autoclave forming of foam sandwich structures. The adhesive achieves a good balance in density, heat resistance, mechanical properties and process properties, and fills the domestic research gap in this field, and further broadens the application range of PMI foam sandwich structures in aerospace and other fields. It has important significance.