SOME APPLICATIONS OF MELAMINE
1. Definition
Melamine is an organic compound, the chemical formula C3H6N6, and the structural formula is shown in Photo 1. This white solid is a trimer of cyanimide (CN2H2). It contains 67% mass of nitrogen. Its derivatives have flame-retardant properties due to the release of nitrogen gas when burned.
Photo 1: Formula of Melamine
2. Basic knowledge background
Melamine was first synthesized by Liebig in 1834. First, calcium cyanamide is converted to dicyandiamide and then heated to the melting point to form melamine. However, nowadays, industrial melamine production processes all use urea according to the following reaction equation:
6 (NH2)2CO → C3H6N6 + 6 NH3 + 3 CO2
The reaction is explained in the following two steps:
The urea first decomposes to form cyanic acid and ammonium, which is endothermic:
6 (NH2)2CO → 6 HCNO + 6 NH3
The cyanic acid then polymerizes to melamine and carbon dioxide gas:
6 HCNO → C3H6N6 + 3CO2
The following reaction is exothermic, but the whole process is endothermic.
3. The common applications of Melamine
Melamine combines with formaldehyde and other agents to produce melamine resin. These resins are high-strength specialty thermoset resins used in high-pressure decorative laminates such as Formica, and laminate.
Photo 2: Melamine application in industrial wood
Melamine is one of the main ingredients in Pigment Yellow 150 dye powder, a colorant in ink and wood paint.
Photo 3: Dye Pigment Yellow Powder 150
Melamine is also used in the production of poly-sulfonates, which are used as superplasticizers to make high-strength concrete. Sulfurated melamine formaldehyde (SMF) is a polymer used as a cement additive to reduce the water content of a concrete while increasing the fluidity and workability of the mixture during construction. The result is concrete with lower porosity and higher mechanical strength, exhibiting resistance to harsh environments and longer service life.
Melamine has been used as a fertilizer for crops since the 1950s and 1960s because of its high nitrogen content (2/3). However, melamine production is much more expensive than other conventional nitrogen fertilizers, such as urea. The mineralization of melamine is slow, making this product economically and scientifically impractical for use as a fertilizer.
Melamine and its salts are used as flame retardants in paints, plastics, and paper. A type of melamine fiber, Basofil, has low thermal conductivity, excellent fire resistance, and is self-extinguishing. This makes it useful for fire protective clothing, either alone or in combination with other fibers.
Photo 4: Melamine acts as a gas-generating agent in anti-expansion paints
In flame retardant coatings, Melamine acts as a gas-generating agent. When heated at a small amount that the gas can escape without restriction, Melamine completely sublimes in the range of 250 - 350oC. However, if the vapor is constrained in any way, then part of the melamine sublimes, which partially undergoes a series of ammonia decomposition to give polycyclic condensation products, known as melam, melem, and melon. Melamine vapors sublimate and ammonia is released acting as flame suppressors.
Photo 5: Melamine's NH3 decomposition reaction chain
Above are some basic knowledge about "SOME APPLICATIONS OF MELAMINE". We hope to provide you with useful information on the use of Melamine.
For further details, please contact Mega Vietnam New Materials Research and Development Center to have the best answers and solutions.
>> Click for more scientific articles <<
Contact
Office Address: Floor 2-A2-IA20, Nam Thang Long Urban Area, Pham Van Dong Street, Dong Ngac Ward, Bac Tu Liem District, Hanoi City, Vietnam
Research Center: Nhue hamlet - Kim Chung village - Dong Anh district - Hanoi - Viet Nam
Website: megaradcenter.com
Tel: (+84) 24 375 89089; Fax: (+84) 24 375 89098
Email: contact@megavietnam.vn
