Plastic The first plastics were made from natural materials like milk, saw dust and cellulose. Parkesine, a forerunner of celluloid, was pres ented by its inventor, Alexander Parkes, at the 1862 Interna tional Exhibition. He made it by treating cellulose with nitric acid and a solvent. Parkesine could be molded when heated and retained its shape once cooled. This allowed Parkes to make all kinds of different objects, such as knife handles, buttons and children’s toys. Together with its durability and light weight, the biggest advantage of today’s plastic is still the fact that it can be molded into practically any shape. Building on some of the early experiments, modern research is increasingly focusing on making plastics from renew able biomass. Air freight unit load devices (ULDs) that are not 100 percent aluminum are made of an aluminum frame with plastic (polycarbonate) panels. Polycarbonate is flame-retardant, impact-resistant and capable of withstand- ing temperatures from -40 to 120°C (-40 to almost 250° F).
100
Powered by FlippingBook