PMI foam is produced by heating methacrylic
acid/methacrylonitrile copolymer sheet and foaming. During the process of foaming the copolymerized sheet, the copolymer is converted into polymethacrylimide. The foaming temperature is above 170oC and varies according to the density and model. In the state of linear elasticity, when the foam body is made of liquid members, the surface tension can pull the material to the edge, leaving only a thin film across the pore surface, which is easily broken.We have a wide range of PMI foam products，for example，PMI foam cores sheet，PMI rigid foam core，PMI composite board,etc.
Thus, although the foam has initially closed cells, its stiffness is entirely derived from the cells and edges, and its modulus is equivalent to that of an open-cell foam. However, the pore surface of PMI foam is composed of real solid parts, and these pore surfaces will increase the stiffness of the porous body. The compression deformation mechanism of closed-cell foams consists of three parts: cell wall bending, edge shrinkage and membrane extension, and the pressure of the enclosed gas.
It can be seen that the strength of the PMI structural foam is related to the relative density, and more importantly, it is related to the volume fraction of the solids contained in the edge of the cell, which is the ratio of the cell edge material to the foam material in the foam structure. The poorer foam fractions are fully open-celled foams, where all the material is rod-shaped at the edges of the pores, and the volume fraction of solids contained in the edges of the pores is equal to 1.
A good PMI foam distribution form is that all foam materials are located at the cell wall of the pores, and the volume fraction of solids contained in the edges of the cells is equal to O, and the relative yield strength is proportional to the relative density. So, expect relatively low values. Compared to other structural foams, ROHACELL (RC) has a lower volume fraction of solids at the cell edges. The range of this ratio is to 0.80.
It can be seen from this that the foam with higher specific shear strength can be obtained by:
developing a new manufacturing process to reduce the volume fraction of solids contained in the edges of the pores; increasing the shear strength of the foam resin; the size of the pores is smaller than The critical diameter for crack propagation or instability; the foam is reinforced with rod-shaped reinforcements.
These are the manufacturer’s descriptions of PMI foam.We also have other PMI foam products, such as PMI foam float body,etc. If you need to contact the manufacturer.