X-RAY FIBRE DIFFRACTION STUDIES OF STRUCTURAL VARIATION IN POLYMER MATERIALS. Watson Fuller, Physics Department, Keele University, Staffordshire, ST5 5BG, UK

Recent developments at the European Synchrotron Radiation Facility (ESRF) and the Daresbury Laboratory Synchrotron Radiation Source (SRS) have allowed a dramatic extension of the structural information which can be obtained in fibre diffraction studies of polymer materials. Three types of application will be described. These are: (i) The exploitation of the high brilliance of the two sources to record diffraction patterns with exposure times as short as 40 milliseconds with the facility for real time display of the accumulating pattern. A Photonics Science CCD detector linked to a Synoptic i860 framegrabber is used to record the pattern and a purpose designed camera allows the development of orientation and crystallinity in polymer materials to be investigated under conditions comparable to those of industrial processing, i.e. draw rates up to 150,000% min, draw ratios up to 4.5 and temperatures up to 350C. This x-ray camera has a video port which allows changes in the gross appearance of a specimen and hence the draw rate and draw ratio at the point in the specimen from which x-ray data is observed to be continuously recorded and displayed during the experiment. (ii) Beamline ID13 at the ESRF with focusing optics which provide an incident beam at the specimen with a diameter of ~ 2 microns has been used with an X/Z stepping stage to investigate the variation in crystallinity and orientation in spherulites of organic polymers and across polymer interfaces and artefacts fabricated from polymer materials. (iii) Beamline 16.1 at the SRS has been developed to allow the simultaneous recording of the variation in small angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) during drawing and annealing of a number of organic polymers, thus allowing the development of lamellae to be correlated with changes in polymer chain conformation and packing.