Plasticizer

A plasticizer is an additive added to polymers to increase their flexibility, workability, and processing characteristics. In plastics, plasticizers are commonly liquids or low‑molecular‑weight solids that blend with polymers such as polyvinyl chloride (PVC) to lower the glass transition temperature and reduce intermolecular forces. This enables increased chain mobility, resulting in greater flexibility, higher elongation at break, and easier processing by extrusion or calendering.

Types and examples: Conventional plasticizers include low molecular weight esters such as phthalates, adipates, and citrates. Non‑phthalate options, such as trimellitates and other specialty esters, are pursued to reduce health and environmental concerns. Polymeric plasticizers (high molecular weight) are designed to be less migratory and more permanently compatible with the host polymer.

Mechanism and effects: Plasticizers insert between polymer chains, increasing free volume and reducing cohesive forces. The result is softer, more pliable materials with lower hardness and stiffness. However, plasticizer migration can occur over time, causing loss of flexibility, odor, and changes in mechanical properties. Processing temperatures can be affected, and long‑term performance may be influenced by aging, heat, and exposure to light.

Applications and considerations: PVC is the major consumer of plasticizers, used in films, cables, flooring, and coated fabrics. They are also used with polyurethane foams, cellulose derivatives, and other polymers. Safety and regulation: certain plasticizers, especially some phthalates, have been linked to health concerns and are restricted in toys and childcare articles in many regions. Substitution with safer or more stable alternatives, including non‑phthalate and polymeric plasticizers, is an ongoing regulatory and industry focus.

Environmental aspects: Plasticizer migration poses environmental and recycling challenges, and lifecycle assessments often consider exposure, toxicity, and end‑of‑life management.