The term "oligomer" is defined, and a survey of methods for the isolation and synthesic of cyclic and linear oligoesters, oligourethanes, oligo(acrylonitri1es) , and oligoamides is presented. The oligomers serve u vaBable function as model substances jou the investigation of many properties of the corresponding high polymers. ThiT ir shown using several exaniples finfrared spectroscopy, X-ray spectroscopy, viscosity).[IS] I. Rotheand M . Rothe, Chem. Ber. 88,284 (1955); M. Rothe,