Plasticizer

Plasticizers (UK: plasticisers) or dispersants are additives that increase the plasticity or fluidity of a material. The dominant applications are for plastics, especially polyvinyl chloride (PVC). The properties of other materials are also improved when blended with plasticizers including concrete, clays, and related products. According to 2014 data, the total global market for plasticizers was 8.4 million metric tonnes.

For plastics

Plasticizers for plastics are additives, most commonly phthalate esters in PVC applications. Almost 90% of plasticizers are used in PVC, giving this material improved flexibility and durability. The majority is used in films and cables. It was commonly thought that plasticizers work by embedding themselves between the chains of polymers, spacing them apart (increasing the "free volume"), and thus significantly lowering the glass transition temperature for the plastic and making it softer; however it was later shown that the free volume explanation could not account for all of the effects of plasticization. For plastics such as PVC, the more plasticizer added, the lower their cold flex temperature will be. Plastic items containing plasticizers exhibit improved flexibility and durability. Plasticizers can become available for exposure due to migration and abrasion of the plastic since they are not bound to the polymer matrix. The "new car smell" is often attributed to plasticizers or their degradation products. However, multiple studies on the makeup of the smell do not find phthalates in appreciable amounts, likely due to their extremely low volatility and vapor pressure.