So xylonite is apparently the first thermoplastic ever invented. Originally patented as Parkesine by its discoverer, Englishman Alexander Parkes, in 1855 as fabric waterproofing, it was shown at the Great Exhibition in London in 1862 where he was awarded a bronze medal. In his early experiments Parkes had experimented with adding camphor to the mix to make a hard substance and had called it xylonite but didn't go any further with it.
Financial difficulties meant Parkes and his associate, Daniel Spill, were unable to develop the process further and Parkes' patents were acquired by an American, John Wesley Hyatt, not long after. Hyatt was interested in using Parkesine to make billiard balls to replace the current ivory ones, and set up the Albany Billiard Ball Company. He and his brother, Isaiah, added camphor to the mix again and patented the resulting substance as celluloid, and established the Celluloid Manufacturing Company to produce it.
Meanwhile, Daniel Spill had formed the Xylonite Co. to take over Parkes' patents and he took legal action against the Hyatt brothers to prevent them marketing their product. This continued for years and in 1884 the final result was that neither company had an exclusive right to the product and, because he had mentioned using camphor in his early experiments and patents, that Alexander Parkes was the inventor of the substance. Both Spill's and the Hyatt's companies were allowed to manufacture the product and over time celluloid became the accepted name for the product.
For those of my generation celluloid was commonplace. It was used to a large degree in photography and film making but it had other uses, too, because it could be moulded and shaped and it replaced ivory in many objects. It wasn't only used to replace ivory, though. My mother had a celluloid doll and I believe table tennis balls are still made of celluloid as are parts of some musical instruments. The main disadvantage of celluloid was that it was highly flammable and, as a result, its place has been overtaken by safer substances. It could also become brittle and fragile when exposed to the air.