Fig 1. Chemical structure formula and three-dimensional structure of 3-Aminopropyltriethoxysilane

3-Aminopropyltriethoxysilane(APS) is an aminosilane frequently used in the process of silanization, the functionalization of surfaces with alkoxysilane molecules. It can also be used for covalent attaching of organic films to metal oxides such as silica and titania. 3-Aminopropyltriethoxysilane is the most popular modification molecule for silicon-based surfaces and leads to the introduction of reactive amine groups onto the surface. 3-Aminopropyltriethoxysilane is normally investigated as silane coupling agent in pretreatment of metal surface for protection of zinc, iron and steel surface[1]. In a recent study, 3-Aminopropyltriethoxysilane has been tested as a corrosion inhibitor for reinforcing steel in alkaline solution[2]. 

The protection mechanism is explained by the adsorption, condensation and dehydration process of silane molecules. When the metal substrate is immersed in silane solution, the silanol groups (Si-OH) can be adsorbed with the metal atoms, while a large number of active silanol groups can condensate and form the silane film with network structure on the metal surface. As the loss of water molecule, the Si-OH group forms stable Si-O-Me covalent bonds with Me-OH, providing a solid inhibitive layer on the metal substrate. Besides, 3-Aminopropyltriethoxysilane is able to provide surface hydrophobicity on porous substrates such as bricks and cements, due to its alkyl group. As surface treatment agents, silane-based products (mainly the mixture of silane and siloxane, containing an alkyl group and several alkoxy groups), could be considered as good water repellents with excellent breathability. 3-Aminopropyltriethoxysilane is used as a glass fiber treatment agent and dental binder, silane coupling agent, and is used in mineral-filled phenolic, polyester, epoxy, PBT, polyamide, carbonate and other thermoplastics.

The thermosetting resin can greatly improve and enhance the physical and mechanical properties and wet electrical properties of the dry and wet flexural strength, compressive strength, shear strength of the plastic, and improve the wettability and dispersibility of the filler in the polymer.    3-Aminopropyltriethoxysilane is an excellent adhesion promoter for polyurethane, epoxy, nitrile, phenolic adhesives and sealing materials. 3-Aminopropyltriethoxysilane can improve the dispersibility of pigments and improve the adhesion to glass, aluminum and iron metal. 3-Aminopropyltriethoxysilane is also suitable for polyurethane and ring. Oxygen and acrylic latex coatings. In resin sand casting, it can enhance the adhesion of resin silica sand and improve the sand strength and moisture resistance. In the production of glass wool and mineral wool, it is added to the phenolic resin binder to improve moisture resistance and increase compression resilience. In the manufacture of the grinding wheel, 3-Aminopropyltriethoxysilane contributes to improving the adhesion and water resistance of the phenolic resin binder of the wear-resistant self-hardening sand.

References

[1] Yang L , Zhang Y , Lei X , et al. Effect of solution concentration on the structures and corrosion inhibition behavior of γ-APS films fabricated on surface of low carbon steel[J]. Journal of Wuhan University of Technology-Mater. Sci. Ed. 2013, 28(2):224-230.
[2] Yan-Qin Z , Li-Xia Y , Peng-Bo X . Research Progress of Application of Silane Coupling Agents in Pretreatment of Metal Surface[J]. Materials Protection, 2017.