Detailed Analysis of Aliphatic Polyurea Crystals

Abstract

A study of the structure and morphology of polyurea-9, polyurea-10, and polyurea-11 crystals was conducted. For the quantitative analysis, these uniaxially drawn samples were examined using wide-angle X ray scattering (WAXS) measurements. The WAXS patterns of the polyurea films suggested a chain-packing configuration similar to that of polyamide crystals, which might indicate the trigonal lattice structure observed for polyamide-10, polyamide-11, polyamide-12. The diffractions of (001) and (002) were strongly dependent on the length of the aliphatic hydrocarbon of polyurea. In addition, we observed the occurrence of transitions from the α-form to the δ-form during heating, and that from the δ-form to the α-form during cooling with insitu synchrotron radiation WAXS measurements. The transitions were similar to the so-called Brill transition in polyamide or nylon films.