(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
