Four major trends in the future development of adhesives in China

In recent years, adhesives have been developing in the direction of low viscosity, high strength, impact resistance, flame retardancy, and other special applications. With the demand for higher performance of underwater adhesives, nanofillers have been added to epoxy adhesives to greatly increase the adhesive strength. The study of the strength, wear resistance, corrosion resistance, and other properties of the adhesive coating, and the reduction of the cost of the adhesive, is gaining attention in the industry.

The study of nanoparticle fillers has become a new topic, among which the intercalation compounding method has been the most widely studied. As early as the 1980s, a polyamide/clay nanocomposite was prepared by a solution intercalation method in foreign countries, and was later melted. Polystyrene/clay nanocomposites were prepared by layer method and the kinetics of melt intercalation was studied. The Institute of Chemistry, Chinese Academy of Sciences also prepared nylon-6/montmorillonite nanocomposites, silicone rubber/montmorillonite composites, and studied their properties and structures. Due to the small size of the dispersed phase in the matrix and the strong interfacial adhesion between the organic and inorganic phases in this method, there are many properties that are superior to conventional composites.

There are many articles on underwater adhesives, but the study of epoxy resin / nano-montmorillonite underwater adhesives has not been found. When cured in air, the shear strength of nano-adhesives is greatly improved compared to ordinary fillers. The shear strength at the time of synergy is equivalent to that of MMT alone, but it has good stability, and due to the addition of ordinary filler, the material cost can be greatly reduced. When cured in water, the shear strength of the MMT alone is lower than that of the normal filler because the delamination of the montmorillonite sheet may be affected. When talcum powder and MMT act synergistically, due to the hydration of talc powder and the strengthening effect of nano-particles, the strength in the water exhibits good stability, and the shear strength changes little with time. It can be seen that the solidified shear strength in air is much better than that in water, and the synergistic effect of the two fillers on the shear strength is high and the stability is good. Epoxy underwater adhesives should be cured in the air whenever possible. At the same time, talc powder and MMT should be added in the basic formula of epoxy resin underwater adhesive, with a ratio of 10:1, and good results can be obtained.