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. The worldwide market for plasticizers in 2000 was estimated to be several million tons per year.

Plasticizers for plastics are additives, most commonly phthalate ester. Almost 90% of the market for plasticizer is for PVC, giving this material improved flexibility and durability. 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. For plastics such as PVC, the more plasticizer added, the lower its cold flex temperature will be. This means that it will be more flexible and its durability will increase as a result of it. Plasticizers evaporate and tend to concentrate in an enclosed space; the "new car smell" is caused mostly by plasticizers evaporating from the car interior.

 Paul Ehrlich (help·info) (14 March 1854 – 20 August 1915) was a German scientist in the fields of hematology, immunology, and chemotherapy, and a Nobel laureate. He is noted for discovering the syphilis treatment salvarsan, the first drug targeted against a specific pathogen; and for his research in autoimmunity, calling it "horror autotoxicus". He coined the term chemotherapy and popularized the concept of a magic bullet.

Paul Ehrlich was born into a Jewish family in Strehlen, in the German Kingdom of Prussia, Province of Silesia (now in Poland). As a schoolboy (inspired by his cousin Karl Weigert who owned one of the first microtomes), he became fascinated by the process of staining microscopic tissue substances. He kept that interest during his studies at the universities of Breslau, Straßburg, Freiburg im Breisgau and Leipzig.

In his dissertation at the University of Leipzig, he picked up the topic again ("Contributions to the Theory and Practice of Histological Staining", Beiträge zur Theorie und Praxis der histologischen Färbung). He married Hedwig Pinkus (then aged 19) in 1883. The couple had two daughters, named Stephanie and Marianne. After his clinical education and habilitation ("The Need of the Organism for Oxygen", Das Sauerstoffbedürfnis des Organismus) at the Charité in Berlin in 1886, he received a call from Robert Koch to join the Institute of Infectious Diseases in Berlin (1891).