plastisoituvuus

The term plastisoituvuus, derived from the Finnish word plastisoituvuus, refers broadly to the capacity of a material to be plastically deformed or softened after the addition of plasticizers or under certain conditions. It is a characteristic commonly discussed in polymer science, materials engineering, and applied physics. Plastisoituvuus manifests when a polymer chain gains mobility, allowing it to slide past neighboring chains without breaking. This property is crucial for a wide range of applications, including flexible packaging, rubber products, and various elastomers.

In practice, plasticizers are low‑molecular‑weight additives that intercalate between polymer chains, reducing intermolecular forces and lowering the glass transition temperature (Tg). When a polymer’s Tg falls below the operating temperature, the material exhibits ductile behavior and significant plastisoituvuus. Classic examples include polystyrene foamed with phthalate esters or polyvinyl chloride treated with dioctyl phthalate. The effectiveness of plasticization depends on chemical compatibility, concentration, and the inherent structural features of the base polymer.

Plastisoituvuus is distinct from other deformation mechanisms such as elastic bending or brittle fracture. While elasticity involves reversible strain, plastisoituvuus denotes permanent shape change under stress. The balance between these behaviors is quantified by stress–strain curves, where the yield point indicates the onset of plastic deformation. Material scientists use indicators such as the Shore hardness scale, tensile modulus, and elongation at break to characterize plastisoituvuus.

Historically, the importance of plasticization grew with the proliferation of synthetic polymers in the mid‑20th century. Early pioneers like Wallace Carothers and the DuPont team discovered that adding plasticizers to synthetic rubbers could tailor flexibility. In contemporary engineering, environmentally friendly plasticizers—such as bio‑based citrate esters—are gaining prominence to reduce health and ecological risks associated with traditional phthalates.