On the relation between long spacings, molecular length, and orientation in long chain compounds with reference to the possibility of chain folding. Part I. Oligomeric amides

In this set of two papers the possibility of chain folding occurring in chain molecules not much longer than the presumed fold length was examined. The present paper deals with oligomeric amides. Following up the preceding work on the relation between long spacing and chain length by Zahn and Pieper on the same compounds, the relation between long spacings and chain orientation was examined in order to assess how far oblique structures could present alternatives to chain folding. It could be concluded that they cannot, the chains remaining straight up to a certain length only (80 A.), beyond which chain folding offers the most probable explanation. The preparation and examination of oriented aggregates required for this conclusion to be reached are discussed. In addition the dependence of the long spacings on the crystallization temperature, and relation between melting point and long spacing are demonstrated, and examples of annealing behavior are given all of which have their corresponding counterpart in the chain‐folded high polymers.