Cyanoacrylates

Cyanoacrylates are a family of strong fast-acting adhesives used in many aspects of modern life. Known for their rapid polymerization upon contact with moisture, cyanoacrylates are widely utilized in both domestic and industrial settings. The chemical bond they form is robust, making them a popular choice for bonding a variety of materials including plastics, metal, wood, and even human skin in medical applications.

History

Cyanoacrylates were discovered during research into materials for clear plastic gun sights for the military during World War II. However, their adhesive properties were not initially considered valuable. It wasn't until the 1950s that cyanoacrylates were commercialized as adhesives.

Chemistry

The main component of cyanoacrylate adhesives is an alkyl cyanoacrylate. These monomers have the general formula C₅H₅N_o2 and polymerize rapidly in the presence of moisture, such as air humidity or the minor amounts of water present on the surfaces to be bonded. This polymerization is an exothermic reaction, releasing heat as the adhesive sets.

Types

There are several types of cyanoacrylate adhesives, each with different properties tailored to specific applications. These include:

• Ethyl cyanoacrylate: The most common type, used for general-purpose bonding.
• Methyl cyanoacrylate: Used where greater strength and resistance to temperature are needed.
• Octyl cyanoacrylate: Developed for medical use, as it is less irritating to skin and has improved flexibility.

Applications

1. 1. 1. Industrial

In the industrial sector, cyanoacrylates are used for assembling electronics, creating o-rings, and bonding small parts in manufacturing processes. Their fast setting time and strong bond make them ideal for high-speed production lines.

1. 1. 1. Medical

Octyl cyanoacrylate is used in medical applications for closing wounds as an alternative to stitches, under the trade names Dermabond and SurgiSeal. This application takes advantage of the adhesive's ability to bond skin quickly and its reduced cytotoxicity compared to other types.

1. 1. 1. Household

In the household, cyanoacrylates are commonly found in the form of "super glue," used for repairing broken items, from ceramics to plastic toys.

Safety and Handling

While cyanoacrylates are invaluable tools, they require careful handling. Direct contact can bond skin and eyes in seconds. They can also release irritating vapors, particularly when used in large amounts or in poorly ventilated areas. Appropriate safety measures, including the use of gloves and eye protection, are recommended.

Environmental Impact

The environmental impact of cyanoacrylates is generally considered low, as they are used in small quantities and polymerize quickly, reducing the risk of environmental release. However, disposal should be handled according to local regulations to minimize any potential harm.