The first completely synthetic plastic, phenol-formaldehyde, was introduced by L. H. Baekeland in 1909,
nearly four decades after J. W. Hyatt had developed a semisynthetic plastic-cellulose nitrate. Both Hyatt
and Baekeland invented their plastics by trial and error. Thus the step from the idea of macromolecules to
the realit y of producing them at wi ll was still not made. It had to wait till the pioneering work of
Hermann Staudinger, who, in 1924, proposed linear molecular structures for polystyrene and natural
rubber. His work broug ht recognition to the fact that the macromolecules really are linear poly mers.