In 1846 he patented the cold cure process for vulcanizing rubber, called by Thomas Hancock "one of the most valuable and extraordinary discoveries of the age".[2] He pioneered the addition of small quantities of phosphorus to metals and alloys, and developed phosphor-bronze (patent 12325 of 1848, taken out jointly with his brother Henry Parkes).[3] In 1850 he developed and patented the Parkes process for economically desilvering lead, also patenting refinements to the process in 1851 and 1852.[4] In 1856, he patented Parkesine - the first thermoplastic - a celluloid based on nitrocellulose treated with a variety of solvents.[5] This material, exhibited at the 1862 London International Exhibition, anticipated many of the modern aesthetic and utility uses of plastics. In 1866 he set up The Parkesine Company at Hackney Wick, London, for bulk low-cost production. It was not, however, a commercial success as Parkesine was expensive to produce, prone to cracking and highly flammable.