Polymers - Definition and Classification

Hermann Staudinger published his research work entitled 'Uber Polymerisation', which was pivotal in the development of modern polymer theory.

Production of polyvinyl chloride resin began in 1927, and it is primarily used to make plumbing lines, pipes, and bottles.

Nylon was synthesized by W. Carothers and is used for ropes, while polystyrene is widely used in packaging, including videocassettes.

<p>Low density and high density polyethylene were developed, commonly used for manufacturing packaging films, pipes, and toys.</p> Signup and view all the answers

<p>By 1976, the polymer plastic industry outstripped steel as the most widely used material. S. Kwolek developed Kevlar, a polymer capable of withstanding temperatures of 300 °C.</p> Signup and view all the answers

<p>A polymer is a macromolecule formed by linking together many monomers. These monomers are small molecules that repeat to create a long chain.</p> Signup and view all the answers

<p>The degree of polymerization refers to the number of repeating units or monomers in a polymer chain. It determines the size of the polymer.</p> Signup and view all the answers

<p>The four classes are: Carbohydrates (sugars), Lipids (fatty acids), Proteins (amino acids), and Nucleic Acids (nucleotides).</p> Signup and view all the answers

<p>Vulcanization makes natural rubber more stable and durable by heating it with sulfur. This process significantly enhances its properties for practical applications like tires.</p> Signup and view all the answers

<p>A polymer consists of a large number of repeating units, while an oligomer contains only a few monomers linked together. Polymers have higher molecular weights compared to oligomers.</p> Signup and view all the answers

<p>Bakelite was the first synthetic plastic, synthesized by Leo Baekeland in 1907. It was significant for its hardness and high heat resistivity, making it a valuable electrical insulator.</p> Signup and view all the answers

<p>Monomers are the basic building blocks of macromolecules, as they bond together to form long polymer chains. The properties of the resulting macromolecule depend on the types and arrangements of these monomers.</p> Signup and view all the answers

<p>British Explorers documented the use of natural rubber by the Mayans, who created balls from it, showcasing one of the earliest applications of polymeric materials. This historical insight highlights the long-standing use of polymers in human culture.</p> Signup and view all the answers

<p>Addition polymerization does not produce by-products, while condensation polymerization typically results in by-products such as water or HCl.</p> Signup and view all the answers

<p>In addition polymerization, the polymer molecular mass is an integral multiple of the monomer's mass, whereas in condensation polymerization, the polymer molecular mass is not an integral multiple.</p> Signup and view all the answers

<p>Longer reaction times are necessary for condensation polymerization to yield higher molecular weight polymers, as the molecular mass increases steadily with time.</p> Signup and view all the answers

<p>Co-polymerization is the process of polymerizing two or more different monomer species together, such as in the production of styrene butadiene rubber, also known as Buna-S.</p> Signup and view all the answers

<p>Addition polymerization can follow free radical or ionic mechanisms, including cationic or anionic processes.</p> Signup and view all the answers

<p>In addition polymerization, the reaction mixture contains monomers, higher polymers, and a small fraction of growing chains, while in condensation polymerization, it contains all types of molecular species including monomers, oligomers, and polymers.</p> Signup and view all the answers

<p>Condensation polymerization reactions are slower because they involve the reaction of two molecular species and often need longer timeframes to reach higher molecular weights.</p> Signup and view all the answers

<p>Addition polymerization typically yields homo-chains, while condensation polymerization results in hetero-polymer chains.</p> Signup and view all the answers

<p>Starch is a polymer of α-D-glucose, while cellulose is a polymer of β-D-glucose.</p> Signup and view all the answers

<p>Natural rubber is the polymer formed by cis-isoprene and is commonly used for making tires and elastic materials.</p> Signup and view all the answers

<p>Biopolymers can be classified as biodegradable or non-biodegradable based on their ability to break down in the environment.</p> Signup and view all the answers

<p>LDPE has a branched structure, making it flexible and less dense, while HDPE has a linear structure, resulting in greater strength and rigidity.</p> Signup and view all the answers

<p>Polyethylene (PE) is used for making bottles and insulation parts, while Nylon is primarily used in textiles and ropes.</p> Signup and view all the answers

<p>Liquid resins are commonly used as adhesives, with epoxy adhesives being a prime example.</p> Signup and view all the answers

<p>Elastomers are a type of polymer that can undergo significant elastic deformation and return to their original shape, such as vulcanized rubber.</p> Signup and view all the answers

<p>HDPE has high tensile strength, stiffness, and impact resistance due to its closely packed molecular structure.</p> Signup and view all the answers

<p>The two functional groups in urethane are an O-R group and an NH-R group.</p> Signup and view all the answers

<p>Polyurethanes are prepared by the polymerization of a di-isocyanate and ethylene glycol.</p> Signup and view all the answers

<p>A blowing agent causes the formation of polyurethane foam during production.</p> Signup and view all the answers

<p>Polyurethane foam is used for furniture stuffing, carpet backings, and insulation.</p> Signup and view all the answers

<p>Polyurethane has high load capacity in both tension and compression and can return to its original shape.</p> Signup and view all the answers

<p>Prof. Otto Bayer demonstrated the creation of polyurethane foam in 1952.</p> Signup and view all the answers

<p>Polyurethanes exhibit good electrical insulating properties.</p> Signup and view all the answers

<p>Polyurethane remains stable with minimal swelling in water, oil, and grease.</p> Signup and view all the answers

<p>Bakelite is a cross-linked polymer, while Novolac is a linear polymer chain.</p> Signup and view all the answers

<p>Bakelite is rigid, hard, and resistant to non-oxidising acids.</p> Signup and view all the answers

<p>Epoxy resin is commonly used as an adhesive for glass and metals.</p> Signup and view all the answers

<p>Vulcanization cross-links rubber, transforming it into a more durable material that can withstand stretching.</p> Signup and view all the answers

<p>Epoxy resin cannot be reclaimed from waste and, therefore, cannot be recycled.</p> Signup and view all the answers

<p>Polar groups in epoxy resin provide excellent adhesive properties.</p> Signup and view all the answers

<p>Bakelite is used in electrical insulator parts due to its excellent electrical insulating properties.</p> Signup and view all the answers

<p>Cold weather can make natural rubber brittle and prone to cracking.</p> Signup and view all the answers