Dissimilar Materials Bonding Using Epoxy Monolith

Abstract

The epoxy monolith with a highly porous structure is fabricated by the thermal curing of 2,2-bis(4-glycidyloxyphenyl)propane and 4,4′-methylenebis(cyclohexylamine) in the presence of poly(ethylene glycol) as the porogen via polymerization-induced phase separation. In this study, we demonstrated a new type of dissimilar material bonding method for various polymers and metals coated with the epoxy monolith. On the basis of scanning electron microscopy (SEM) observations, the pore size and number of epoxy monoliths were evaluated to be 1.1–114 μm and 8.7–48 200 mm –2 , respectively, depending on the ratio of the epoxy resin and cross-linking agent used for the monolith fabrication. Various kinds of thermoplastics, such as polyethylene, polypropylene, polyoxymethylene, acrylonitrile–butadiene–styrene copolymer, polycarbonate bisphenol-A, and poly(ethylene terephthalate), were bonded to the monolith-modified metal plates by thermal welding. The bond strength for the single lap-shear tensile test of stainless steel and copper plates with the thermoplastics was in the range of 1.2–7.5 MPa, which was greater than the bond strength value for each bonding system without monolith modification. The SEM observation of fractured test pieces directly confirmed an anchor effect on this bonding system. The elongated deformation of the plastics that filled in the pores of the epoxy monolith, was observed. It was concluded that the bond strength significantly depended on the intrinsic strength of the used thermoplastics. The epoxy monolith bonding of hard plastics, such as polystyrene and poly(methyl methacrylate), was performed by the additional use of adhesives, solvents, and a reactive monomer. The epoxy monolith sheets were also successfully fabricated and applied to dissimilar material bonding.

Interfacial Structure Control and Three-Dimensional X-ray Imaging of an Epoxy Monolith Bonding System with Surface Modification

“…This is consistent with the results of the SEM observation for the cross sections of the same material (Figure 4a). This was different from the previously reported result 24 where a skin layer with a certain thickness was observed on the untreated metal plate. Actually, the number of the pores at the interfacial area seemed to be smaller than that for the inner position in the present study.…”

“…The penetration of molten plastics into the monolith pore has already been reported. 23,24 In this study, the SEM and 3D X-ray imaging methods were used to confirm the penetration of the plastics. Both methods revealed the close contact of the PET plate to the monolith surface, as shown in Figures S7 and S8.…”

“…We have already reported that epoxy monoliths are useful for dissimilar material bonding of metals such as a stainless steel (SUS), copper (Cu), and aluminum (Al) in combination with various thermoplastics such as polyethylene, polypropylene, poly(oxymethylene), ABS resin, poly(ethylene terephthalate) (PET), and polycarbonate bisphenol-A (PC). 24 In this monolith bonding system, an epoxy monolith layer was prepared by thermosetting on a metal substrate, and then the thermal welding of a polymer was performed on the monolith surface. the anchor effect of the plastics penetrating the pores of the monolith.…”

Photoadhesive of Acrylates Containing Cross-links of Dipyridyl Disulfide

“…For adhesion of two adherends of dissimilar materials [1][2][3][4][5], modification of their surface with laser, plasma or chemicals has been used in general. On the other hand, adhesives having catechol or its analogue moieties have been paid attention, because polymers having catechol moieties show high adhesive strength toward various kinds of aherends [6][7][8][9].…”

Co-continuous network polymers using epoxy monolith for the design of tough materials

“…A monolith with a three-dimensional continuous network skeleton and through holes has been applied as a high-performance material, of which a high porosity and strength are used for the separation, reaction, and other functions 29,30 , e.g., HPLC columns 31,32 , supports for catalysts 33 , separators for lithium-ion batteries 34 , and dissimilar materials bonding [35][36][37] . We now propose a new strategy for the synthesis of toughened polymer materials using an epoxy monolith.…”