Polymere

Polymere are large molecules built from repeating units called monomers. Through covalent bonds, these units assemble into long chains that can be linear, branched, or crosslinked. The length and architecture of a polymer determine its physical properties, including strength, elasticity, thermal behavior, and chemical resistance.

Polymere can be natural or synthetic. Natural polymers include cellulose, proteins, DNA, starch, and natural rubber. Synthetic polymers include polyethylene, polystyrene, polyvinyl chloride, nylon, and poly(methyl methacrylate). The properties and applications of polymers arise from the choice of monomer, molecular weight, and chain structure, such as tacticity and crystallinity.

Synthesis. Polymerization forms polymers from monomers. It is broadly categorized into addition (chain-growth) polymerization, where active centers add monomers, and condensation (step-growth) polymerization, where small molecules are released. Many techniques employ catalysts or initiators to control molecular weight, architecture, and functionality.

Applications and properties. Polymere are used in packaging, textiles, automotive parts, electronics, medicine, and construction. They offer low density, toughness, chemical resistance, and design flexibility, with properties tuned through processing (molding, extrusion) and additives.

Environmental and history. Environment: persistence and recycling challenges, with ongoing development of biodegradable polymers and recycling technologies. History: modern polymer science advanced in the 20th century, with notable milestones such as the invention of Bakelite and nylon, and extensive research into polymer physics.