Over the years, much emphasis has been laid on polymers, their desirable properties and their vast range of applications. Monomers, the building block of polymers, have been brushed aside, to the extent that they are defined only in the context of a polymer. By definition, “a monomer is a molecule that, as a unit, binds chemically to other molecules to form a polymer.”
The word ‘Monomer’ comprises two root words – ‘mono-’ meaning ‘one’ and ‘-mer’ which means ‘part’. A large number of monomer units combine to form polymers through a process called polymerization. When the comprising monomer units are of a smaller number (up to a few dozen), the resultant is an oligomer. These oligomers could bedimers, trimers, tetramers, pentamers, hexamers, heptamers, octamers, nonamers, decamers, dodecamers, eicosamers, etc. depending on whether they have 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, or 20 monomer units, respectively.
Classifications of Monomers:
Based on the substance they are derived from, monomers can further be classified as Acrylic Monomers, Allyl Monomers, Amine Monomers, Anhydride Monomers, Biodegradable Polymer Monomers, Bisphenol and Sulphonyl Diphenol Monomers, Carboxylic Acid Monomers, Epoxide Monomers, Isocyanate Monomers, Silicone Monomers, etc. For instance, Methyl Methacrylate (MMA) monomer, manufactured by Sumitomo Chemical Asia, is one of the most popular acrylic monomers, derived from methacrylic acid.
Properties of Monomers:
Polyfunctionality is a distinguishing property of monomers. The functionality of a monomer is the number of covalent bonds (bonds with other monomer units) it can form in a polymer chain. Bifunctional monomers can form only two bonds, giving rise to linear, chainlike polymers. Monomers of higher functionality can form more number of bonds, resulting in cross-linked, network polymers. Polyfunctionality is thus an essential feature of a monomer.
Another noteworthy point is that monomers have much lower molecular weights than their oligomer or polymer counterparts. For instance, the molecular weight of MMA monomer is 100.117 g/mol, while that of its polymer Polymethyl Methacrylate (PMMA), is naturally much higher, depending on the number of monomer units in the chain.
Applications of Monomers:
Though their primary application has been to facilitate the manufacture of polymers, monomers find themselves useful in a wide range of applications. Methyl methacrylate is by far the most commonly produced methacrylate monomer. Here are some of its applications:
- Its versatility allows it to be used to produce a pure homopolymer (PMMA or Acrylic Glass) or, in combination with other monomers, to obtain numerous polymers with varied valuable properties. MMA is also used as a key raw material to produce other methacrylate monomers.
- Owing to its adhesive properties, MMA is used to manufacture adhesives and sealant chemicals.
- MMA is also used in various chemical processes as finishing agents, intermediates, and processing aids.
- Adapted to be used as paint additives and coating additives, MMA is also used in solvents (in which it becomes a part of a product formulation or mixture).
- MMA also finds its use in products including inks, toners, personal care products and water treatment products.
Interested to know more about Monomers, how they are manufactured and used? We’ll be happy to answer your queries. Reach out to Sumitomo Chemical Asia, a leading manufacturer of MMA monomer and PMMA polymer.