Diethyltoluenediamine: Uptake, Distribution, and Enhanced Properties in Polyurethaneurea and Epoxy Resins

General Description

The research on Diethyltoluenediamine in male Sprague Dawley rats revealed its uptake and distribution patterns, highlighting rapid absorption in the gastrointestinal system and bladder, with predominant urinary excretion within 24 hours. In PUU dispersions, Diethyltoluenediamine as a chain extender showed superior physical properties compared to ethylenediamine, particularly enhancing water resistance and mechanical strength. Moreover, in epoxy resin blend-curing with polyoxypropyleneamines, Diethyltoluenediamine improved impact strength, heat resistance, and adhesive properties, offering enhanced mechanical and thermal characteristics ideal for diverse industrial applications such as coatings, adhesives, and composites.

Figure 1. Diethyltoluenediamine

Uptake and distribution

Diethyltoluenediamine (CAS 68479-98-1) is a chemical compound developed by Albermarle Corporation as a substitute for toluenediamine (TDA) in certain applications. In a study on the uptake and distribution of Diethyltoluenediamine in male Sprague Dawley rats, groups of 4 adult rats were orally administered [3H]-labeled Diethyltoluenediamine at a dose of 179 pmol/kg body weight. Tissues were collected at various time points over a period of 48 hours. The results showed high levels of label in the gastrointestinal system and bladder within the first 8 hours, with moderate levels found in the liver and kidney. The highest concentration of radioactivity in most tissues, excluding specific organs, was observed at the 4-hour time point. Thyroid levels were found to be the highest at 24 and 48 hours. By 8 hours, urinary excretion became the primary route of elimination, with over 60% of the labeled compound excreted by 24 hours. Only a small amount of label remained in the tissues after 6 days. In a separate experiment to determine urinary and fecal excretion patterns, it was revealed that Diethyltoluenediamine was primarily eliminated through the urinary system, with the majority of the label excreted within the first 24 hours. Furthermore, the Diethyltoluenediamine isomer exhibited a higher rate of excretion compared to the Diethyltoluenediamine isomer. Overall, these findings provide valuable insights into the uptake and distribution, as well as the elimination patterns of Diethyltoluenediamine in male Sprague Dawley rats, shedding light on its metabolic fate within the body. ¹

Applications as chain extender

Diethyltoluenediamine is commonly used as a chain extender in the preparation of polyurethaneurea (PUU) aqueous dispersions. When compared to ethylenediamine (EDA) as a chain extender, Diethyltoluenediamine has shown to improve the physical properties of the PUU dispersions significantly. The PUU dispersions prepared with Diethyltoluenediamine exhibited similar or even superior physical properties when compared to those prepared with EDA. In particular, the water resistance and mechanical properties of the Diethyltoluenediamine-extended PUU films were notably enhanced. These enhancements can be attributed to the strong hydrogen bonding present in urea carbonyl groups and the ordered structure of hard segments within the systems. A specific formulation of DETDA-extended PUU film, containing 40% hard segment and 4.0% DMPA unit, demonstrated the lowest water-absorbing capacity among all the PUU films tested, at 2.6%. Additionally, by modifying the surface of the Diethyltoluenediamine-extended PUU film with aminoethylaminopropyl polydimethylsiloxane (AEAPS), the hydrophobicity of the film was further enhanced with an increase in AEAPS content. ²

Enhanced properties of epoxy resins

Diethyltoluenediamine is commonly used in the blend-curing of epoxies along with polyoxypropyleneamines such as Jeffamine® D-230 and D-400. This blending process has been studied to understand its impact on the curing processes and physical properties of epoxy resins. The main objective of this research is to assess how different types and ratios of curing agents affect the typical properties of epoxies. The mixtures of Jeffamine® and Diethyltoluenediamine have been found to result in cured epoxy systems that exhibit improved impact strength compared to those cured with Diethyltoluenediamine alone. Furthermore, epoxies cured with these blends demonstrate significantly higher heat deflection temperature, modulus, and hardness when compared to epoxies cured with Jeffamine® alone. One key finding is that the adhesive strength of the cured epoxy systems reaches a maximum at an intermediate blending ratio of the curing agents. This suggests that the combination of Diethyltoluenediamine and polyoxypropyleneamines can enhance various mechanical and thermal properties of epoxy resins, making them suitable for a wide range of applications in industries such as coatings, adhesives, and composites. ³

Reference

1. BABIN M C. The Uptake and Distribution of Diethyltoluenediamine in the Male Sprague Dawley Rat. 1900.

2. Lin J, Chun PH, Yong LC. Polyurethaneurea aqueous dispersions prepared with diethyltoluenediamine as chain extender. Journal of Coatings Technology and Research. 2007. 4(1): 59-66.

3. Huang JC, Ying TC. Blend-Curing of Epoxies with Jeffamine? and Diethyltoluenediamine. Journal of Polymer Engineering. 1996. 16(1): 51-72.

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