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 reality of producing them at will 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 brought recognition to the fact that the macromolecules really are linear polymers.
After this it did not take long for other materials to arrive. In 1927 poly(vinyl chloride) (PVC) and
cellulose acetate were developed, and 1929 saw the introduction of urea-formaldehyde (UF) resins.