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Polymer vs. Monomer
Posted: February 12, 2008
Industry expert Tony O'Lenick compares and contrasts the difference between polymers and monomers.
A polymer is a chemical composed of many repeat units. These repeat units can be composed of one monomer, two or more monomers or blocks of smaller polymers. While there is a blurry line between the molecular weight different of polymers and oligimers, polymers are normally defined as molecules that have a molecular weight over 5,000 g/mol. While this simple term is easily understood, the number of different types of monomers and chemistries used to connect the monomers is truly staggering.
A monomer is the small reactive molecule, which are chemically bonded to other monomers to form a polymer. The reactive group can be one that reacts when exposed to radical generating materials (chain growth polymerization), or one that reacts when two different type of reactants are added in the proper ratio with the proper catalyst and temperature (condensation polymerization). Polymers are high molecular weight species that are made up of many repeat units. One major difference between polymers and small molecules (monomers) are the characteristics that polymers exhibit. Polymers normally have higher viscosities, higher boiling points and can show improved mechanical strength over small molecules (monomers).
When we think of polymers we generally think of man-made materials that include polyacrylates (made by chain growth polymerization), fibers like nylon and polyester (which are made by condensation polymerization) and the numerous plastics that make up a large part of our world. While these polymers provide products we use everyday, most people fail to recognize that life itself depends upon polymers. Naturally occurring polymers, including proteins, enzymes, DNA, RNA cellulose, and polysaccharides, are critical to life processes. In evaluation the use of natural or synthetic polymers in personal care products, the monomer (and its properties) the chemistry used to make the polymer (catalysts and the like) and the polymer itself need to be considered.