The "poison" of ethylenediamine has two meanings, one is toxicity and the other is cancer.

Regarding toxicity, everyone who knows something about chemistry knows that ethylenediamine is a toxic liquid, which is inherently toxic.

Regarding the "cancer", it is reflected in the national standard specification of the reinforcement industry. The mandatory provisions in GB50550-2010 "Code for Acceptance of Construction Quality of Building Structure Reinforcement Engineering" 4.4.5 are as follows. In the reinforcement project, it is strictly forbidden to use structural adhesives whose main component of the curing agent is unknown or the main component of the curing agent is ethylenediamine.

Why is ethylenediamine called a "cancer"? This also has to start from the development history of reinforcement materials. First, let's understand what ethylenediamine is.

What is ethylenediamine?

Ethylenediamine is a colorless or slightly yellow oily or watery liquid with an ammonia-like odor and is strongly alkaline. (n26D) 1.4540. Flammable, low toxicity, median lethal dose (rat, oral) 1460mg/kg. Corrosive, mainly used for solvents and analytical reagents. Ethylenediamine vapor is strongly irritating to mucous membranes and skin. Contact with the vapor of this product can cause conjunctivitis, bronchitis, pneumonia or pulmonary edema, and contact dermatitis may occur. In addition, ethylenediamine can also cause liver and kidney damage, and direct contact with its liquid on the skin and eyes can cause burns. This product can cause occupational asthma.

What are the dangers of being the main component of the curing agent?

Ethylenediamine is low in cost. As a curing agent, the strength of the glue is also very high after curing. It is generally used as the main agent of the curing agent in the epoxy resin glue used for reinforcement in the early days. But over time, some of its dangers have come to the fore. First of all, ethylenediamine is a flammable and explosive liquid, and it is a major safety hazard in itself, whether it is in storage, transportation or construction. It is also toxic and highly volatile, and can easily cause serious damage to the respiratory tract, digestive tract and skin of the construction workers.

Moreover, the glue using ethylenediamine curing agent can be tested for short-term strength after curing. However, after a long time, its strength will fail very quickly, and its toughness is insufficient and brittle.

Even if there is no problem in the construction process, it has passed the quality acceptance of the reinforcement project, but it does not mean that it can be done once and for all and sit back and relax. If ethylenediamine is contained in the glue, the colloid is likely to be brittle and peeled off in the subsequent service life, resulting in collapse, which seriously endangers the life safety of building users.