Two years into the worldwide Great Depression, which began in the United States on October 29, 1929, Plexiglas™ and Lucite™ - polymethyl methacrylate (PMMA) - were invented in two different companies’ laboratories on two different continents.
Polyethylene was first discovered by two chemists at ICI in England by accident in 1933. After five years of R&D efforts, commercialization became possible.