Poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated
[CAS# 102782-92-3]

Identification

• Classification: Chemical reagent >> Organic reagent >> Siloxane
• Name: Poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated
• Synonyms: Siloxanes and Silicones, 3-((2-aminoethyl)amino)propyl Me, di-Me, methoxy-terminated
• CAS Registry Number: 102782-92-3
• EC Number: 600-354-1

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Hazard Statements: H315-H318
• Precautionary Statements: P264-P264+P265-P280-P302+P352-P305+P354+P338-P317-P321-P332+P317-P362+P364

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Serious eye damage	Eye Dam.	1	H318
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

Poly\[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated, is a functional organosilicon polymer that belongs to the class of aminofunctional siloxanes. It consists of a polysiloxane backbone incorporating pendant aminoethylaminopropyl groups and is terminated with methoxy (-OCH₃) groups at each end. This structure imparts a unique balance of reactivity, flexibility, and compatibility with various organic and inorganic substrates, making it valuable in coatings, adhesives, surface treatments, and personal care formulations.

The siloxane backbone is composed primarily of repeating –Si(CH₃)₂–O– units, typical of polydimethylsiloxanes (PDMS), which provide flexibility, thermal stability, and low surface tension. Attached to some of the silicon atoms in the chain are side groups consisting of 3-((2-aminoethyl)amino)propyl substituents. These groups introduce primary and secondary amine functionalities, giving the polymer high reactivity toward electrophilic species and providing strong adhesion to various surfaces, including glass, metal, and certain plastics.

The terminal methoxy groups are hydrolyzable alkoxy groups that can undergo hydrolysis and subsequent condensation reactions in the presence of moisture. This feature allows the polymer to form crosslinked networks or covalent bonds with silanol-containing surfaces such as silica, glass, or metal oxides. These reactions are typically utilized in sol-gel processes, surface priming, or as curing mechanisms in silicone-based adhesives and coatings.

Poly\[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated, was developed to enhance the interfacial bonding properties of silicone materials while retaining their inherent thermal and oxidative stability. The presence of aminoalkyl groups significantly improves substrate wetting, pigment dispersion, and compatibility with polar resins and additives.

In industrial applications, this polymer is commonly used in formulations for primers, paints, and sealants. It functions as a coupling agent that promotes adhesion between organic polymers and inorganic surfaces. It is also used to modify resin matrices in composite materials to improve mechanical properties and durability. The reactive amino groups can participate in curing reactions with epoxy resins, isocyanates, or acid chlorides, enabling the polymer to become chemically integrated into cured networks.

In personal care and cosmetic applications, lower molecular weight forms are used as conditioning agents. They provide excellent spreading and lubricity, while the amino functionality enhances their ability to deposit onto hair and skin. This results in long-lasting conditioning and a smooth, non-greasy feel.

From a chemical safety standpoint, poly\[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated, is generally considered low in toxicity when used in properly formulated products. However, due to the presence of reactive amine groups, it can cause irritation in high concentrations or unreacted form. Therefore, it is important to assess and control exposure during product development and application.

In summary, poly\[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane, methoxy terminated, is a highly functionalized silicone polymer offering a combination of silicone flexibility, moisture-reactive terminal groups, and amino functionality. These characteristics support its wide use in adhesion promotion, surface modification, and specialty formulations across various industries including coatings, electronics, and personal care.