Polymérm

Polymérm is not a standard term in polymer science; the widely used terms are polymer in English and polymère in French. In general, a polymer is a large molecule composed of repeating structural units called monomers that are covalently bonded to form long chains or networks.

Polymers vary in size, architecture and properties. They can be linear, branched or crosslinked, and their physical characteristics depend on the identity of the monomers, the way they are linked, and the molecular weight distribution. Key properties include strength, elasticity, toughness, and chemical resistance. Thermal behavior is described by glass transition temperature (Tg) and, for crystalline polymers, melting temperature (Tm). Crystallinity and tacticity (arrangement of side groups) also influence performance.

Synthesis of polymers falls into two broad classes. Addition (chain-growth) polymerization builds chains from active growing ends, using catalysts or initiators such as free radicals or metal complexes. Condensation (step-growth) polymerization joins monomers with the loss of small molecules like water or methanol. Common methods include radical polymerization, Ziegler–Natta and metallocene catalysis, polycondensation and polyaddition.

Polymers are categorized as natural or synthetic. Natural polymers include cellulose, starch, proteins and nucleic acids. Synthetic polymers cover polyethylene, polypropylene, polystyrene, polyvinyl chloride and nylons, among others. Biopolymers and biodegradable polymers (such as polylactic acid) are developed for specific environmental or biomedical purposes.

Applications span packaging, textiles, automotive, electronics, and medicine. Environmental considerations focus on recycling, degradation and lifecycle impacts, as many polymers persist in the environment. The science continues to explore sustainable materials, recycling technologies and alternatives to conventional plastics.