A polymer is a chemical which is characterized by having extremely long molecules. This tends to give polymers useful properties such as flexibility and elasticity. Polymers have the highest molecular weight among any molecules, and may consist of billions of atoms. Human DNA is a polymer with over 20 billion constituent atoms.
Polymers are made from monomers; smaller chemical compounds which are linked together to form longer molecules. Polyethylene, for example, is made by reacting the simple molecule ethylene (CH2CH2) such that it joins to itself repeatedly. The majority of these monomers are derived from petrochemicals. In fact, about 4 percent of the oil produced worldwide goes to making polymers. This use of a substantial quantity of a precious non-renewable resource is one environmental consequence of plastics.
They are not always straight chains of regular repeating monomers; sometimes they consist of chains of varying length, or even chains that branch in multiple directions. Residual monomers are often found together with the polymers they create, giving the polymers additional properties. To coax monomers to link together in certain configurations requires a variety of catalysts–secondary molecules which speed up reaction times. Catalysts are the basis of most synthetic polymer production.
Since most polymers are not “natural” but rather synthetic, they are generally not biodegradable. Many plastics also do not readily break down due to natural forces, such as high temperatures or sunlight. In some ways, this resilience is a positive aspect of plastics since it enables us to make durable, long lasting polymer items, but when plastics are thrown away, they create significant problems by piling up in landfills. Approximately one quarter of all domestic trash in landfill sites is composed of various polymers.
Proteins, or the polymers of amino acids, and many other molecules that make up life are polymers. Boc-L-Valine, also known as N-(tert-Butoxycarbonyl)-L-valine or L-Valine,N-[(1,1-dimethylethoxy)carbonyl]- (CAS:13734-41-3), serves as the amino acid protection monomer. Certain polymers are so complex that they cannot be readily identified, so techniques such as wide angle x-ray scattering, small angle x-ray scattering, and small angle neutron scattering are employed. Most polymers are organic, employing carbon bonds as their backbone. Others use silicon. Because of the great diversity of polymers, there are many that have yet to be discovered, offering a fruitful field for further research and development.