Polymers are large molecules made from repeating structural units called monomers, which are joined together by covalent bonds. These monomers can be simple molecules like ethylene (in polyethylene) or more complex structures such as styrene (polystyrene). The nature and arrangement of the monomers dictate the properties of the polymer, allowing for a wide range of applications, from plastic bags to DNA. The process of forming polymers from monomers is known as polymerization, which can occur via various mechanisms, including addition (chain-growth) polymerization and condensation (step-growth) polymerization. The versatility of polymer chemistry means that polymers can be engineered to be lightweight, durable, and flexible, making them integral to numerous industries, including packaging, construction, healthcare, and electronics.

Polymers are large molecules made from repeating structural units called monomers, which are joined together by covalent bonds. These monomers can be simple molecules like ethylene (in polyethylene) or more complex structures such as styrene (polystyrene). The nature and arrangement of the monomers dictate the properties of the polymer, allowing for a wide range of applications, from plastic bags to DNA. The process of forming polymers from monomers is known as polymerization, which can occur via various mechanisms, including addition (chain-growth) polymerization and condensation (step-growth) polymerization. The versatility of polymer chemistry means that polymers can be engineered to be lightweight, durable, and flexible, making them integral to numerous industries, including packaging, construction, healthcare, and electronics.

Polyvinyl chloride (PVC) is made through a polymerization process of vinyl chloride monomers (VCM). The production starts with ethylene and chlorine, which combine to create ethylene dichloride (EDC). EDC is then thermally cracked at high temperatures to form VCM. Once VCM is purified, it undergoes polymerization, often initiated by free radicals, to form PVC. This can be done using different methods, such as suspension, emulsion, or bulk polymerization, depending on the desired properties of the PVC. The polymerization process is carefully controlled to obtain PVC with the targeted molecular weight and structure. Following polymerization, the PVC is separated, washed, and dried to yield the final product, which can then be compounded with additives to enhance its properties for various applications, from construction materials to everyday goods.

Freshwater pearls are dyed using a variety of methods to enhance or change their color, aiming to meet fashion demands or preferences. The process often involves immersing the pearls in a dye solution. The most common method uses organic dyes, chosen for their compatibility with the pearl's nacre, ensuring the color penetrates effectively without damaging the pearl’s surface. Additionally, heat may be applied to help the dye adhere better. The time pearls spend in the solution can vary, depending on the desired intensity of the color. It's a delicate process requiring skill to achieve uniform coloring without compromising the pearl's luster. However, it's crucial to note that dyed pearls should be cared for properly as the color can fade over time, especially when exposed to harsh chemicals or direct sunlight.