Organic+-+Polymerisation

Without [|polymers], mankind couldn't exist. People use manmade plastics such as [|polypropylene] and [|polyvinyl chloride] (i.e., PVC) in hospitals, schools and their own homes. Yet, man-made plastic accounts for only a small percentage of polymers. Rubber and cellulose, which are natural polymers, are used to make everything from tires to cellophane to [|rayon]. Deoxyribonucleic acid (i.e., [|DNA]) and protein are also natural polymers. As important as polymers are, they wouldn't exist without monomers, which are small, single molecules such as [|hydrocarbons] and [|amino acids]. These monomers bond together to form polymers. The process by which these monomers bond is called polymerization. Polymerization isn't a complicated subject, but the ways in which monomers are put together vary so much that scientists find it easier to have more than one system of describing  polymerization. One system of separating polymerization  processes asks the question of how much of the original molecule is left when the monomers bond. In "addition polymerization  ", monomers are added together with their structure unchanged. This kind of polymerization  could be likened to a kid playing with a Lego set. The Legos put together make a larger structure, but in the end the individual Legos are still discernable. Not so in condensation polymerization. This process results in a [|polymer] that is less massive than the two or more monomers that joined to form it. This happens because not all of the original [|monomer] is allowed to stay on the polymer. [|Hydrogen] chloride and water are usually thrown from the mix when polymers form in this manner. A good analogy might be what happens when kids try to make a popsicle-stick village. The popsicle itself has to be discarded (most often through eating!) in order to be able to use the stick itself. While the condensation versus addition systems of describing polymerization  may be useful, it is not the only way to see how polymers might form. Another way of explaining how monomers form polymers involve observing how the monomers combine with one another. In chain growth polymerization , one monomer is added to the collection at a time until a polymer is formed. This is the simplest process of polymerization. A more complicated process is called step-growth polymerization. Here, it isn't just one monomer joining the party at a time. It can happen that way, but it's also possible for a group of monomers to show up together. Eventually, there will be enough monomers to create a polymer. Polymerization is a necessary process. Only through this forming of larger molecules could the human brain exist. In actuality, nothing at all could exist without polymerization , for without a brain to experience life and define its processes, there would be no reason to exist.
 * Polymerisation**

Monomers are molecules typically about 4-10 atoms in size, reactive in that they bond readily to other monomers in a process called //[|polymerization]//. Polymers and their polymerization processes are so diverse that a variety of different systems exist to classify them. One major type of polymerization is //condensation polymerization//, where reacting molecules release water as a byproduct. This is the means by which all proteins are formed. Polymers 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. In //copolymerization//, polymers are formed that contain two or more different monomers. Larger, more complex polymers tend to have higher melting points and tensile strengths than others, due to the wealth of intermolecular forces acting between their constituents. 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].
 * Polymers**
 * Polymers** are molecules which consist of a long, repeating chain of smaller units called //monomers//. 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. Proteins, or the polymers of [|amino acids], and many other molecules that make up life are polymers. Polymers are the largest and most diverse class of known molecules. They even include plastics.