When was plastic invented?

Alexander Parkes presented his invention Parkesine at the Great International Exhibition in London in 1862. His invention, which could be molded into a shape while hot and then maintain that shape as it cooled, is considered the first man-made plastic.

Parkes's compound was derived from cellulose, which became the basis for celluloid. Celluloid was invented by John Wesley Hill eight years after Parkes presented Parkesine. The most common use of celluloid was in the making of film. During the late 19th century and the early part of the 20th century, inventors experimented with adding formaldehyde to celluloid to create resins.