Measurement of crystallinity in drawn polyethylene terephthalate fibres by X-ray diffraction

Abstract

A method has been devised for the measurement of crystallinity in drawn fibres of polyethylene terephthalate fibre by an X-ray technique. Strictly monochromatic X-ray radiation is used and the X-ray camera is evacuated. This enables the photographic film, which is used to record the X-ray reflexion, to be free of "white" radiation and parasitic X-ray radiation normally termed "air scatter". The results show that the crystallinity in drawn yarns is much lower than expected and that no correlation exists between the crystallinity so measured and the density of the yarns.