The effect of melt processing conditions on the hydrogen-bonded sheet orientation and polarization of nylon 11 films

Abstract

Abstract : It is known that melt-quenched, cold-drawn, and then annealed nylon 11 films possess a particular doubly oriented hydrogen-bonded sheet structure: the hydrogen-bonded sheets being in the plane of the film and the molecular chain direction being in the direction of draw. In this study, nylon 11 was melted at 210 deg C in a hot press for different melting times (ranging from 30 seconds to 20 minutes) prior to quenching into an ice-water bath. The resulting orientation of the hydrogen-bonded sheet structure in these films following quenching, cold-drawing, and then annealing for the uniaxially drawn-annealed samples, and following quenching and then annealing for the undrawn-annealed samples, was examined using wide-angle x-ray diffraction and F.T.I.R spectroscopy. The results showed that for short times in the melt, films which are subsequently cold-drawn and then annealed exhibit a double orientation but as time in the melt increases, a change to a random orientation of the sheet structure about the draw (chain direction) is obtained. These results show that for melt quenched films with short times in the melt, a degree of preferred orientation of the hydrogen-bonded sheets in the plane of the film occurs. As time in the melt increases, the preferred orientation in the plane decreases. However, following cold drawing and several cycles of polarization using a maximum field of 150 MV/m at room temperature, the uniaxially drawn films processes from films with different times in the melt possessed the same final orientation of the hydrogen-bonded sheets in the film thickness direction and the same remanent polarization.