Structure of semirigid polyamides with bulky groups in backbone

The structure of a range of systematically synthesized polyamides, as well as some corresponding component molecular fragments, were studied using wid e angle X-ray scattering and computer modeling methods. The molecules all c ontained tetra-substituted biphenyls within the amide components, while the aliphatic acid components contained different lengths of the alkyl sequenc e. A model representing the molecular packing in fiber samples is proposed. It indicates that the polymer backbones are organized in a distorted hexag onal lattice while the intervening pendant side groups still remain randoml y packed. (C) 1999 John Wiley & Sons, Inc.