Polymer synthesis is the process of creating large molecules called polymers from smaller units known as monomers. This can be achieved through various methods, including addition polymerization and condensation polymerization. In addition polymerization, monomers with unsaturated bonds react to form long chains, while in condensation polymerization, monomers join together, releasing small molecules like water. The choice of synthesis method affects the properties of the resulting polymer, such as its strength, flexibility, and thermal stability. Common examples of synthetic polymers include polyethylene, used in plastic bags, and nylon, used in clothing and ropes.