<P> The development of plastics has evolved from the use of natural plastic materials (e.g., chewing gum, shellac) to the use of chemically modified, natural materials (e.g., natural rubber, nitrocellulose, collagen, galalite) and finally to completely synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride). Early plastics were bio-derived materials such as egg and blood proteins, which are organic polymers . In around 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines . Treated cattle horns were used as windows for lanterns in the Middle Ages . Materials that mimicked the properties of horns were developed by treating milk - proteins (casein) with lye . </P> <P> In the nineteenth century, as industrial chemistry developed during the Industrial Revolution, many materials were reported . The development of plastics also accelerated with Charles Goodyear's discovery of vulcanization to thermoset materials derived from natural rubber . </P> <P> Parkesine (nitrocellulose) is considered the first man - made plastic . The plastic material was patented by Alexander Parkes, in Birmingham, England in 1856 . It was unveiled at the 1862 Great International Exhibition in London . Parkesine won a bronze medal at the 1862 World's fair in London . Parkesine was made from cellulose (the major component of plant cell walls) treated with nitric acid as a solvent . The output of the process (commonly known as cellulose nitrate or pyroxilin) could be dissolved in alcohol and hardened into a transparent and elastic material that could be molded when heated . By incorporating pigments into the product, it could be made to resemble ivory . </P> <P> In 1897, the Hanover, Germany mass printing press owner Wilhelm Krische was commissioned to develop an alternative to blackboards . The resultant horn - like plastic made from the milk protein casein was developed in cooperation with the Austrian chemist (Friedrich) Adolph Spitteler (1846--1940). The final result was unsuitable for the original purpose . In 1893, French chemist Auguste Trillat discovered the means to insolubilize casein by immersion in formaldehyde, producing material marketed as galalith . </P>

When was the first piece of plastic made