Match the following: List \(\mathbf{1}\) 1\. Phenol + formaldehyde 2\. Terephthalic acid \(+\) ethylene glycol 3\. Caprolactam 4\. Butadiene \(+\) styrene List 2 (1) Synthetic rubber (2) Bakelite (3) Nylon-66 (4) Terylene

Condensation polymerization is a type of chemical reaction where monomers join together losing small molecules as byproducts, such as water or methanol. An everyday example is the synthesis of Bakelite, which originates from the reaction of phenol with formaldehyde. The process involves the phenolic OH groups of phenol and the aldehyde groups of formaldehyde condensing to form -OH links, releasing water molecules in the process.

This reaction not only creates a network of interconnected phenolic resins, yielding a hard and thermosetting polymer, but it also showcases the principles of step-growth polymerization. During this process, polymer chains grow step by step, forming small oligomers first, which later combine into long chain polymers.

An esterification reaction is a chemical reaction that forms an ester as the reaction product from an organic acid and an alcohol, typically with the elimination of water. In the synthesis of polymers like Terylene, an ester bond is formed between terephthalic acid and ethylene glycol. This esterification process is a key component of forming polyesters, a category of polymers widely used in fibers for clothing, containers for liquids and foods, and thermoplastic engineering materials.

During the reaction, the acid group (COOH) of terephthalic acid and the hydroxyl group (OH) of ethylene glycol react to form an ester linkage (CO-O) and water. The repeating ester linkages extend into long molecular chains that characterize Terylene, display strong material properties such as resistance to stretching and resilience, making it valuable for fabrics like polyester.

Ring opening polymerization (ROP) is a form of chain-growth polymerization where the terminal end of a polymer acts as a reactive center where new monomer molecules can add on. This type of reaction is unique because it involves the opening of a cyclic monomer such as caprolactam. The process includes splitting the monomer's ring structure to form the polymer chain, leading to materials such as Nylon-66.

During the ring opening of caprolactam, the ring's tensile strain is relieved and a long-chain polyamide is formed. This technique is advantageous for creating polymers with uniform structures and properties, which are often utilized in technical components and textile fibers thanks to their mechanical strength, elasticity, and abrasion resistance.

Copolymerization is a polymerization technique that involves multiple monomer species coming together to form copolymers, resulting in a material that possesses properties of both monomers. For instance, the reaction between butadiene and styrene forms styrene-butadiene rubber (SBR), a synthetic rubber. This rubber combines the toughness of polybutadiene with the abrasion resistance of polystyrene.

By varying the ratio of butadiene to styrene, it's possible to tailor the physical properties of the resulting copolymer, making it a versatile material for applications like automobile tires, shoe soles, and adhesives. In addition to SBR, other well-known copolymers include ABS (acrylonitrile butadiene styrene) and Nitrile rubber, showcasing the diversity and customizability accessible through copolymerization.

Synthetic polymers are man-made chains of molecules created by polymerization reactions, which include a wide range of plastics, rubbers, and fibers, such as those we encounter in the exercise: Bakelite, Terylene, Nylon-66, and synthetic rubber. They are engineered to have specific properties that suit the demands of various applications, from packaging and construction to electronics and clothing.

The molecular structure of these polymers—whether linear, branched, or cross-linked—determines their mechanical properties and ultimate application. These materials have become indispensable due to their durability, low cost, and versatile nature. They are a testament to the incredible advancements in material science and the profound impact of chemical engineering on daily life.