poliolefin

Poliolefin, or polyolefin, is a family of thermoplastic polymers produced from olefin (alkene) monomers, such as ethylene and propylene. The polymers are saturated hydrocarbons with simple hydrocarbon backbones, offering a combination of chemical resistance, clarity, toughness, and processability. The most important commercial polyolefins are polyethylene (PE) and polypropylene (PP).

Polyethylene encompasses several grades, including high-density (HDPE), low-density (LDPE), and linear low-density (LLDPE), differing mainly in branching and density, which influence stiffness and clarity. Polypropylene exists in tactic forms (atactic, isotactic, syndiotactic), with isotactic PP being the most widely used due to high stiffness and heat resistance. Polyolefins are produced by polymerization of olefin monomers using catalysts such as Ziegler-Natta or metallocenes. Polymerization can be conducted in gas, slurry, or solution processes, often in large-volume facilities.

Properties vary by grade and structure but generally include good chemical resistance, low moisture uptake, good electrical insulation, and relatively low density. They are relatively inexpensive and can be tailored for stiffness, toughness, and clarity, making them versatile for molding and extrusion. Common applications include packaging films and bags, bottles and containers, pipes and fittings, automotive and electrical components, and consumer goods. Environmental considerations focus on recyclability; PE and PP are among the most widely recycled plastics. Polyolefins are typically not biodegradable and can accumulate in waste streams if not properly managed.