Bis[3-(trimethoxysilyl)propyl]amine (BTMSPA) is a bis-amino silane which can be used as a water based coupling agent that promotes the adhesion between different materials to form a hybrid material. The amino groups in the polymer provide coating strength to the modified metal surfaces and the silanol groups bond with the hydroxyls present on the surface of metals which are further cured to give metal-siloxane linkages [1]. As silane coupling agents, BTMSPA has the ability to form a durable bond between organic and inorganic materials. Because the hydrolyzable group forms stable condensation products with siliceous surfaces and other oxides such as those of aluminum, zirconium, tin, titanium, and nickel, meanwhile, the organofunctional group alters the wetting or adhesion characteristics of the substrate, utilizes the substrate to catalyze chemical transformations at the heterogeneous interface, orders the interfacial region, or modifies its partition characteristics, and significantly effects the covalent bond between organic and inorganic materials [2].

The following example shows the function of BTMSPA in adhesion improvement. Silane-based surface treatment of metals has emerged in recent years as a promising alternative for chromate treatment in the metal-finishing industry. Organosilane coatings offer effective corrosion protection on metals such as aluminum and steel. Hydrophobic silanes such as bis[triethoxysilyl]ethane and bis[triethoxysilylpropyl]tetrasulfide are particularly effective in corrosion protection. Unfortunately, volatile organic compounds (VOCs) such as methanol and ethanol cannot be avoided during the preparation of coatings from hydrophobic precursors. Development of environmentally benign corrosion-protection coatings, therefore, is the driver for understanding the fundamental properties of water-based silane films.
A mixture of bis[trimethoxysilypropyl]amine (bis-aminosilane, A) and vinyltriacetoxysilane (VTAS, V) is an outstanding candidate among water-based silanes, with comparable corrosion protection to the organic-solvent-based silanes on many metal substrates. According to previous work,6 the following advantages have been observed for the bis-aminosilane and VTAS mixture coatings: (1) the mixture is water soluble; (2) the system hydrolyzes rapidly in the water yet does not gel; and (3) the system exhibits broader compatibility with paints than most silanes.

Bis-aminosilane is hydrophilic, traceable to the secondary amine-bridging group, which promotes good bonding to metal substrates. However, bis-aminosilane is not stable by itself and gelation occurs soon after mixing with water. VTAS, on the other hand, is hydrophobic and not readily hydrolyzable in water. Interestingly, when the two silanes are mixed at certain ratios, rapid hydrolysis, higher stability, good bonding, and good corrosion-protection performance are achieved [3]. 

BTMSPA also has other functions in application. It can be used to synthesize an amine modified mesostructured organosilica with 1,2-bis(triethoxysilyl)ethane (BTESE) for potential applications in catalysis and absorbance. Metal finishing may be devised by coating BTMSPA and vinyltriacetoxysilane which can be used for protection against corrosion. Also, Bis[3-(trimethoxysilyl)propyl]amine, a silsesquioxane precursor may be used to synthesize hybrid mesostructured organosilica materials.

Scheme1 Chemical structure of bis-aminosilane and VTAS: (a) bis[trimethoxysilylpropyl]amine (bis-aminosilane) and (b) vinyltriacetoxysilane (VTAS).

References

[1] https://www.sigmaaldrich.com/catalog/product/aldrich/413356?lang=en&region=US

[2] https://www.gelest.com/product/SIB1833.0/

[3] Yiming Wang etc.,Water-Barrier Properties of Mixed Bis[trimethoxysilylpropyl]amine and Vinyltriacetoxysilane Films, J. Phys. Chem. B 2007, 111, 25, 7041-7051.

[4] https://pubchem.ncbi.nlm.nih.gov/compound/157882