plastiques

Plastics, or plastiques in French, are a broad class of solid materials composed mainly of polymers that can be shaped when soft and hardened by heat or chemical treatment. Most are synthetic polymers derived from petrochemicals, though some are bio-based. Plastics are broadly categorized as thermoplastics, which soften when heated and can be remolded, and thermosets, which cure permanently and resist remelting.

A polymer is a long chain of repeating units called monomers. Common plastics include polyethylene (HDPE and LDPE), polypropylene, polystyrene, polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polycarbonate. Additives such as stabilizers, plasticizers, colorants, and flame retardants are often included to tailor properties. Bioplastics like polylactic acid (PLA) and polyhydroxyalkanoates (PHA) are produced from biomass.

Production methods include polymerization of monomers and processing techniques such as extrusion, injection molding, blow molding, film casting, and thermoforming. Plastics are used in packaging, construction, automotive, electronics, textiles, and consumer goods.

Environmental aspects: Plastics are persistent in the environment and can fragment into microplastics, raising concerns for ecosystems and human health. Management includes mechanical recycling, chemical recycling, energy recovery, and disposal in landfills. Recycling rates and feasibility depend on polymer type and infrastructure. Policy measures in many regions address waste, labeling, and producer responsibility, including bans or fees on certain single-use items.

Research aims to improve recyclability, reduce hazardous additives, and develop sustainable or biodegradable alternatives while maintaining performance and safety.