(1) the chemical bond theory, the
silane coupling agent contains two kinds of different chemical functional groups, one end of which can react with inorganic materials, such as glass fiber, silicate, metal oxide and other surface.
(2) surface infiltration theory that silane coupling agent increases the surface tension of glass fiber and other inorganic materials, even so that it is greater than the surface tension of resin matrix, which is in favor of the resin in the inorganic surface infiltration and expansion, improvement in the resin of inorganic enhanced the wettability, the resin and inorganic reinforcing better materials bonded together.
(3) deformation layer theory, that the silane coupling agent in the interface is plastic, it can form a larger than 10 nm flexible deformation layer at the interface, the deformation layer has destroyed self healing ability, not only can the interfacial relaxation prestressed, and to prevent the crack extension, so it can improve the interface bonding strength.
(4) constrained layer theory, it is believed that there is a boundary zone between the high modulus and low modulus of composite materials, and the silane coupling agent is a part of the composite material. Silane coupling agent can not only bonded with the inorganic surface, but also can with reaction resin groups to the polymer "tight beam at the interface. When the modulus of the interface zone is between the inorganic reinforcing material and the resin, the stress can be transmitted uniformly.
(5) reversible hydrolysis theory, which is considered to have the water in the presence of the silane coupling agent and the glass fiber by the stress and the role of the fracture, but can be a reversible re healing. In this way, the rigid region (which is formed by the coupling agent and silane coupling agent) is also allowed to be relaxed, and the chemical bond theory, the constraint layer theory and the deformation layer theory are also available. This mechanism not only can explain the mechanism of interfacial coupling, but also shows the effect of the relaxation stress and the effect of anti - water - protection surface.
Inorganic pigments and fillers in coating liquid organic phase dispersion can be divided into wetting, depolymerization and stabilization (Kang Xuning) 3 stages. Because of these inorganic pigments and fillers, the surface is easy to adsorb on the surface of water, so the hydrophobic material is difficult to be wetted and dispersed. With silane coupling agent of inorganic pigments and fillers were pre treatment (surface modification), silane will replace pigment or filler on the surface of the water, coated particles and the R groups outward, become lipophilic, hydrophobic, and easy to be base material wetting. After wetting, the base material molecules are inserted into the inorganic pigment or filler particles, which separates them, so that they can disperse stably and prevent the precipitation and agglomeration. After treatment with silane coupling agent, inorganic pigment and filler surface reduce the structural function of the coating, so that the viscosity of the coating is greatly reduced, and the added amount of pigment and filler can not affect the flow.
标签： Silane Coupling Agent
