Polymer vs Monomer
Monomers and polymers are important in various aspects. When someone hears the word polymer, they automatically think about synthetic polymers like polyethylene, PVC or nylon. Other than these, there is also a category of polymers known as biopolymers such as carbohydrates, proteins, nucleic acids, which are crucial to our life. From food, we take these biopolymers or their monomers into our bodies, so that our body can produce energy and other necessary molecules using these. It is also important to know the differences between monomers and their relative polymers, to have an understanding about their synthesizing processes.
Monomers are building blocks of polymers. They can be simple or a complex molecule with double bonds or another functional group like –OH, -NH2, –COOH, etc. The unsaturated double bonds or functional groups are needed in the polymerization process, when several monomers are linking to form a polymer. Normally, there are two functional groups in both sides of the monomer, so it can form linear chains by binding to other molecules from both sides. If there are several functional groups, monomers can link to form branched polymers. For example, glucose is the common monomer of carbohydrates with –OH functional groups. When joining two glucose molecules, a water molecule is released and forms a glycoside bond. When the –OH in C-1 joins with a –OH group in C-4 of another glucose molecule, a linear chain will form. But if –OH of C-6 joins with a -OH of C-1 of another glucose the chain will be branched. Moreover, amino acids are the monomers of protein and nucleotides are the monomers of nucleic acid. Other than the above mentioned biopolymers, there are synthetic polymers as well. For example, Ethene/Ethylene molecule has a carbon- carbon double bond, and it is the monomer of polyethylene.
Polymers are large molecules, with repeating structural units of monomers. These monomers are bonded to each other with covalent bonds to form a polymer. They have a high molecular weight, and consist over 10,000 atoms. In the synthesis process, which is known as polymerization, longer polymer chains are obtained. There are two main types of polymers depending on their synthesis methods. If the monomers have double bonds between carbons, from addition reactions polymers can be synthesized. These polymers are known as addition polymers. In some of the polymerization reactions, when two monomers are joined, a small molecule like water is removed. Such polymers are condensation polymers. Polymers have very different physical and chemical properties than its monomer. Moreover, according to the number of repeating units in the polymer, properties differ. There are a large number of polymers present in the natural environment, and they play very important roles. Synthetic polymers are also used widely for different purposes. Polyethylene, polypropylene, PVC, nylon, Bakelite are some of the synthetic polymers. When producing synthetic polymers, the process should be highly controlled to get the desired product always. Synthetic polymers are used as adhesives, lubricants, paints, films, fibers, plastic goods, etc.
Difference between Polymer and Monomer
- Monomer is a single molecule, and polymer is a collection of molecules, which are joined together.
- Monomers have a small molecular weight, whereas the polymers have a larger molecular weight, which is many times of the weight of a monomer.
- Monomers and polymers differ in their chemical and physical properties. For example, glucose is an oxidizing sugar, soluble in water, has a sweet taste. But starch is a non-oxidizing sugar, partially soluble in water and don’t have a sweet taste.
- Polymers usually have higher boiling points, higher mechanical strengths over monomers.