Ingeniously Harries suggested that in fact there were no end groups, that these modified units combined to form a ring structure, two units to a ring. Most polymer plastics are formed through the application of heat and pressure. Thermoplastic polymers can be reheated and reshaped after once being molded. Thermosetting polymers retain their shapes even at relatively high temperatures and cannot be reformed. The tie that binds.
Most polymers contain atoms held in a molecular structure by covalent bonds.
These bonds are formed through the sharing of electrons, electrically charged particles within an atom. Sharing electrons reduces the energy level of the individual atoms. These bonds are maintained until other chemical reactions encourage atom combinations which yield lower energies. Staudinger had studied polyketenes, materials derived from the compound ketene and believed by many to have a ring structure similar to that proposed by Harries for rubber. Staudinger suggested that the end groups on this long chain were no different from the other groups in the molecule.