FTIR AND X-RAY STUDY OF POLYMORPHS OF NYLON-11 AND RELATION TO FERROELECTRICITY

Nylon-11 polymorphs have been studied by x-ray diffraction and by infr ared spectroscopy. A gamma or gamma-like phase of Nylon-11 was produce d by treating the metastable delta' phase with gaseous HCl or DCl and then exposing the resulting complex (amidonium salt) to 100% RH H2O or D2O vapor. An oriented form of the gamma or gamma-like phase results from treatment of the oriented delta' phase, but stretching of the uno riented gamma or gamma-like phase, obtained by treatment of the unorie nted delta' phase, induces a transformation to the ct phase stable at room temperature. The use of DCl and D2O produced highly deuterated sa mples with Fermi resonances indicating the relative strengths of the h ydrogen bonds are weakest in the a phase, intermediate in the delta' p hase and strongest in the gamma or gamma-like phase. (C) 1994 John Wil ey and Sons, Inc.