nonpolymerized

Nonpolymerized describes material that has not been converted into a polymer. In polymer chemistry, polymerization is the process by which monomer units join to form long macromolecules. A nonpolymerized substance may be a free monomer, an oligomer that has not fully linked, or a portion of monomer present within a partially cured system.

Many processes produce a mixture of polymer and unreacted monomer, known as the residual or nonpolymerized fraction. Full conversion is often unattainable in practice due to limited initiation efficiency, temperature, curing time, inhibitors, mixture viscosity, or diffusion constraints.

Remnant monomer can act as a plasticizer, lowering strength and increasing solubility, or alter thermal properties. It may pose health or safety risks because of volatility or toxicity, so appropriate handling, ventilation, and cure monitoring are important. Quality control often reports conversion percentages or residual monomer content.

Nonpolymerized material is relevant in coatings, adhesives, dental resins, and other resins where the degree of cure governs performance. In material design and processing, descriptions of nonpolymerized content help predict stability, aging, and leaching behavior.