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Published by BDMAEE on 2025-04-07

Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE) in Low-Odor Epoxy Resin Formulations: A Comprehensive Overview

Introduction

Epoxy resins are widely used thermosetting polymers renowned for their excellent adhesive properties, chemical resistance, and mechanical strength. They find applications in diverse industries, including coatings, adhesives, composites, and electronics. However, a significant drawback of many epoxy resin formulations is the presence of volatile organic compounds (VOCs) and unpleasant odors, often stemming from the curing agents or accelerators used. These odors can pose health risks and environmental concerns, limiting their applicability in enclosed spaces and sensitive environments.

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE), a tertiary amine catalyst, presents a compelling alternative for formulating low-odor epoxy resin systems. This article provides a comprehensive overview of BDMAEE, focusing on its properties, mechanism of action, advantages in reducing odor, applications, handling precautions, and future trends.

1. Chemical Identity and Physical Properties

BDMAEE is a tertiary amine catalyst belonging to the ether amine family. Its chemical structure, properties, and parameters are crucial for understanding its functionality in epoxy resin formulations.

Chemical Name: Bis[2-(N,N-Dimethylaminoethyl)] Ether
Synonyms: Dimorpholinodiethyl ether, DMDEE, JEFFCAT ZF-10, DABCO DME
CAS Registry Number: 3033-62-3
Chemical Formula: C₁₂H₂₆N₂O
Molecular Weight: 214.35 g/mol

Table 1: Physical Properties of BDMAEE

Property	Value	Unit	Reference
Appearance	Colorless to Pale Yellow Liquid	–	[1]
Density (20°C)	0.85 – 0.86	g/cm³	[2]
Boiling Point	189-190	°C	[3]
Flash Point (Closed Cup)	71-74	°C	[4]
Viscosity (20°C)	2.5 – 3.5	cP	[2]
Refractive Index (n20/D)	1.440 – 1.445	–	[1]
Solubility (Water, 20°C)	Soluble	–	Internal Data
Amine Value	520-530	mg KOH/g	[2]

2. Mechanism of Action as an Epoxy Curing Accelerator

BDMAEE functions as a highly efficient tertiary amine catalyst in epoxy resin curing reactions. Its mechanism involves two primary pathways:

Anion Generation: BDMAEE facilitates the ring-opening polymerization of epoxy resins by abstracting a proton from hydroxyl groups present in the resin or a co-reactant (e.g., alcohol). This generates an alkoxide anion, a powerful nucleophile that attacks the epoxide ring, initiating chain propagation.
```
R-OH + BDMAEE <=> R-O- + BDMAEE-H+
```
Coordination Catalysis: BDMAEE can coordinate with the epoxide oxygen, activating the epoxide ring towards nucleophilic attack. This coordination weakens the C-O bond in the epoxide, making it more susceptible to reaction with nucleophiles such as hydroxyl groups or amines.
```
Epoxide + BDMAEE <=> [Epoxide---BDMAEE] (activated complex)
```

The synergistic effect of these two pathways makes BDMAEE a potent accelerator, enabling rapid curing even at relatively low concentrations. The ether linkage in BDMAEE enhances its flexibility and availability of the amine groups, contributing to its high catalytic activity.

3. Advantages of BDMAEE in Low-Odor Formulations

The primary advantage of BDMAEE lies in its ability to produce low-odor epoxy resin formulations compared to traditional amine curing agents, particularly those with lower molecular weights or higher volatility.

Reduced Volatility: BDMAEE has a relatively high molecular weight and lower vapor pressure compared to many conventional amine curing agents like diethylenetriamine (DETA) or triethylenetetramine (TETA). This lower volatility translates to reduced emissions of odorous amines during and after the curing process.
Improved Amine Blushing Resistance: Amine blushing is a phenomenon observed with amine-cured epoxy resins, especially under humid conditions. It involves the reaction of amine curing agents with atmospheric carbon dioxide and moisture, forming carbamates that appear as a white, hazy film on the surface. BDMAEE-cured systems exhibit improved resistance to amine blushing due to the catalyst’s lower reactivity towards atmospheric CO₂ and its efficient incorporation into the polymer network.
Faster Cure Rates: BDMAEE’s high catalytic activity allows for faster cure rates at lower concentrations. This reduces the overall exposure time to uncured resin and minimizes the potential for odor generation.
Enhanced Chemical Resistance: Properly formulated BDMAEE-cured epoxy resins exhibit excellent chemical resistance, similar to those cured with traditional amine curing agents. This is crucial for applications where the cured material will be exposed to harsh chemicals or solvents.

Table 2: Comparison of Odor and Volatility of Different Curing Agents

Curing Agent	Molecular Weight (g/mol)	Boiling Point (°C)	Odor Level (Subjective)	Volatility (Relative)
Diethylenetriamine (DETA)	103.17	207	Strong, Pungent	High
Triethylenetetramine (TETA)	146.23	277	Strong, Ammoniacal	Medium
Isophorone Diamine (IPDA)	170.30	247	Moderate, Amine-like	Medium
Bis[2-(N,N-Dimethylaminoethyl)] Ether (BDMAEE)	214.35	189-190	Mild, Amine-like	Low

Note: Odor Level is subjective and varies based on individual sensitivity. Volatility is a relative comparison.

4. Applications of BDMAEE in Epoxy Resin Formulations

BDMAEE finds applications in a wide array of epoxy resin formulations where low odor and rapid cure are desirable.

Coatings:
- Floor Coatings: BDMAEE is used in self-leveling epoxy floor coatings for residential, commercial, and industrial applications. The low-odor characteristic makes it suitable for use in occupied spaces.
- Protective Coatings: Used in protective coatings for metal structures, pipelines, and chemical storage tanks, offering excellent chemical resistance and corrosion protection with minimal odor.
- Waterborne Epoxy Coatings: BDMAEE can be incorporated into waterborne epoxy systems as a co-catalyst to enhance cure speed and film properties.
Adhesives:
- Structural Adhesives: Employed in structural adhesives for bonding metals, plastics, and composites in automotive, aerospace, and construction industries. The low-odor property is beneficial in enclosed manufacturing environments.
- Electronics Adhesives: Used in electronics assembly for bonding components to printed circuit boards (PCBs), providing good electrical insulation and mechanical strength.
Composites:
- Fiber-Reinforced Polymers (FRPs): Utilized in the manufacturing of FRP composites for aerospace, automotive, and marine applications. The faster cure rates facilitated by BDMAEE can improve production efficiency.
- Tooling Resins: Used in tooling resins for creating molds and patterns, offering good dimensional stability and heat resistance.
Encapsulation Compounds:
- Electronics Encapsulation: Used as a catalyst in epoxy formulations for encapsulating electronic components, providing protection against moisture, dust, and mechanical stress. The low-odor characteristic is important for worker safety and comfort in electronics manufacturing facilities.

5. Formulation Considerations and Optimization

Optimizing epoxy resin formulations with BDMAEE requires careful consideration of various factors, including resin type, hardener type, stoichiometry, and other additives.

Resin Selection: BDMAEE is compatible with a wide range of epoxy resins, including bisphenol-A epoxy resins, bisphenol-F epoxy resins, epoxy novolacs, and cycloaliphatic epoxy resins. The choice of resin depends on the specific application requirements, such as viscosity, glass transition temperature (Tg), and chemical resistance.
Hardener Selection: While BDMAEE primarily acts as an accelerator, it is typically used in conjunction with a primary amine or anhydride hardener. The type and amount of hardener significantly influence the cure rate, mechanical properties, and chemical resistance of the cured epoxy. Aliphatic amines, cycloaliphatic amines, and polyamidoamines are commonly used hardeners.
Stoichiometry: The stoichiometry of the epoxy resin and hardener should be carefully controlled to ensure complete curing and optimal properties. An excess or deficiency of either component can lead to incomplete curing, reduced mechanical strength, and increased odor.
Concentration of BDMAEE: The optimal concentration of BDMAEE typically ranges from 0.1% to 5% by weight of the resin-hardener mixture. The exact concentration depends on the desired cure rate and the reactivity of the resin and hardener. Higher concentrations of BDMAEE can accelerate the cure but may also reduce the pot life of the mixture.
Additives: Various additives can be incorporated into epoxy resin formulations to modify their properties, such as fillers, pigments, plasticizers, and flame retardants. Fillers can improve mechanical strength, reduce shrinkage, and lower cost. Pigments provide color and opacity. Plasticizers enhance flexibility. Flame retardants improve fire resistance.

Table 3: Example Epoxy Formulation with BDMAEE

Component	Weight (%)	Function
Bisphenol-A Epoxy Resin	50	Resin
Polyamidoamine Hardener	45	Hardener
BDMAEE	2.0	Accelerator
Fumed Silica	3.0	Thixotrope

6. Handling Precautions and Safety Information

BDMAEE, like other chemical compounds, should be handled with care. Following proper safety procedures is essential to minimize potential health risks.

Skin and Eye Contact: BDMAEE can cause skin and eye irritation. Wear appropriate personal protective equipment (PPE), such as gloves, safety glasses, and protective clothing, when handling the material. In case of skin contact, wash thoroughly with soap and water. In case of eye contact, flush with plenty of water for at least 15 minutes and seek medical attention.
Inhalation: Inhalation of BDMAEE vapors can cause respiratory irritation. Ensure adequate ventilation when working with the material. Use a respirator if necessary.
Ingestion: Do not ingest BDMAEE. If ingested, seek medical attention immediately.
Storage: Store BDMAEE in a cool, dry, and well-ventilated area away from incompatible materials, such as strong acids and oxidizing agents. Keep containers tightly closed to prevent moisture contamination.
Disposal: Dispose of BDMAEE and contaminated materials in accordance with local, state, and federal regulations.

7. Advantages and Disadvantages of Using BDMAEE

Table 4: Advantages and Disadvantages of BDMAEE

Feature	Advantages	Disadvantages
Odor	Lower odor compared to traditional amine curing agents	Still possesses a mild amine-like odor, may not be completely odorless.
Cure Rate	Faster cure rates at lower concentrations	May reduce pot life of the mixture.
Volatility	Lower volatility, reduced emissions
Blushing	Improved amine blushing resistance
Properties	Excellent chemical resistance and mechanical properties
Cost		Can be more expensive than some traditional amine curing agents.
Handling		Requires proper handling and safety precautions.

8. Alternatives to BDMAEE

While BDMAEE offers significant advantages in low-odor epoxy formulations, other catalysts and curing agents can be considered as alternatives, depending on the specific application requirements and cost constraints.

Modified Amines: Modified amines, such as Mannich bases and amidoamines, can provide lower odor and improved compatibility with epoxy resins.
Tertiary Amine Blends: Blends of tertiary amines with different functionalities can be used to optimize cure rate and odor profile.
Latent Catalysts: Latent catalysts, such as boron trifluoride complexes, require activation by heat or other stimuli, providing long pot life and controlled curing.
Anhydride Curing Agents: Anhydride curing agents offer good chemical resistance and electrical properties but typically require higher curing temperatures.

9. Market Trends and Future Outlook

The demand for low-VOC and low-odor epoxy resin formulations is steadily increasing due to growing environmental awareness and stricter regulations. This trend is driving the adoption of BDMAEE and other similar catalysts in various industries. Future research and development efforts are likely to focus on:

Developing novel catalysts with even lower odor and improved performance.
Optimizing epoxy resin formulations for specific applications.
Exploring new applications for BDMAEE in emerging fields, such as bio-based epoxy resins and sustainable coatings.
Improving the cost-effectiveness of BDMAEE to make it more competitive with traditional curing agents.

10. Conclusion

Bis[2-(N,N-Dimethylaminoethyl)] ether (BDMAEE) is a valuable tertiary amine catalyst for formulating low-odor epoxy resin systems. Its lower volatility, improved amine blushing resistance, and faster cure rates make it an attractive alternative to traditional amine curing agents in various applications, including coatings, adhesives, composites, and electronics. Careful formulation considerations, proper handling precautions, and ongoing research and development efforts will further enhance the performance and broaden the applicability of BDMAEE in the future. As environmental regulations become more stringent and consumer demand for low-odor products increases, BDMAEE is poised to play an increasingly important role in the epoxy resin industry.

References

[1] Sigma-Aldrich. (n.d.). Bis[2-(N,N-dimethylaminoethyl)] ether. Product Information.

[2] Air Products and Chemicals, Inc. (n.d.). DABCO® DME catalyst. Product Data Sheet.

[3] PubChem. (n.d.). Bis(2-(dimethylamino)ethyl) ether. National Center for Biotechnology Information.

[4] BASF. (n.d.). Lupragen® N 205. Product Information.

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