plasticized

Plasticized describes a material that has undergone plasticization, a process that increases plasticity and flexibility by introducing plasticizers or by chemical modification. In polymer science, plasticization lowers the glass transition temperature and reduces brittleness, enabling large strains without cracking. The resulting material is often called a plasticized polymer or plasticized plastic. The most familiar example is plasticized polyvinyl chloride (PVC-P), where small molecule plasticizers such as di(2-ethylhexyl) phthalate or other esters are incorporated between polymer chains.

Mechanism and effects: Plasticizers insert themselves between polymer chains, reducing interchain interactions and increasing free volume, which enhances mobility of the chains. External plasticizers dissolve in the polymer matrix; internal plasticization involves covalent modification of the polymer with plasticizable groups. Properties depend on compatibility, molecular size, and volatility; migration of the plasticizer to the surface or environment is a common issue, affecting mechanical properties and odor. Different plasticizers offer trade-offs between flexibility, durability, and safety.

Applications and safety: Common plasticizers include phthalates, adipates, and citrates, as well as non-phthalate alternatives for reduced toxicity. Polymeric or high-molecular-weight plasticizers can reduce migration. Plasticized materials are used in flexible films, cables, roofing membranes, medical tubing, and packaging. Regulatory concerns about certain plasticizers have spurred the development of safer substitutes and considerations for recyclability and environmental impact.