Plasticizers are additives used with plastics and vinyls to improve their flexibility and resistance. They are typically made of lightweight, volatile molecules that are either non-polymeric materials or polymer impact modifiers. Many plasticizers can also help control viscosity and aid in dispersion of additives like fillers and pigments.1 Phthalates are often used as plasticizers to make polyvinyl chloride (PVC) more pliable.2 Other materials that often use plasticizers include cellulose acetate and cellulose nitrate. Plasticizers can be found in a number of industrial products, such as plastics, glues, caulks, paints, building materials, and vinyl floors. They are also used in household products like shower curtains, cleaning supplies, food packaging, toys, soap, shampoo, and nail polish. 3

Plasticizers make substances more flexible by reducing the chemical affinity between molecules.4

When a polymer plasticizes it generally undergoes several changes. It becomes less rigid at room temperature, the temperature at which it can be molded significantly is reduced, and it becomes easier to elongate at room temperature. This transformation happens by adding a comonomer to improve flexibility and shock resistance and reduce crystallizability and the brittle point.5 Some plasticizers can chemically modify the plastic material without modifying the base polymer.6

Because plasticizers are often semi-volatile and unstable, they can cause harm to the environment and human health. Although bioconcentration factors (BCFs) vary between plasticizers, toxic plasticizers like phthalates and BPA accumulate in the body, and can cause damage to the liver, kidneys, lungs, and reproductive system.7 These can also cause cancer and harm children’s cognitive and reproductive development. Babies exposed to phthalates also have a higher rate of asthma and allergies.8

  1. Plastics Design Library
  2. Parsons School of Design’s Healthier Materials & Sustainable Building Certificate Program
  3. The Center for Disease Control: Phthalates Fact Sheet
  4. Plastics, The Environment and Human Health
  5. American Chemical Society: Principles of Plasticization
  6. Plastics Design Library
  7. Healthcare Without Harm
  8. Six Classes: Bisphenols + Phthalates

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