An instrument for the collection of simultaneous small and wide angle x-ray scattering and stress-strain data during deformation of polymers at high strain rates using synchrotron radiation sources

A fully integrated system has been developed which allows the study of the deformation of synthetic polymers by simultaneous small- and wide-angle x-r ay scattering (SAXS/WAXS) and stress-strain techniques at synchrotron radia tion sources. Two-dimensional x-ray data collection is achieved via two cha rge coupled device based area detectors which provide video signal outputs. A video extensometer provides sample strain and cross-section data during deformation. All three video signals are processed by a powerful Synoptics i860 processor based video framegrabber, with no loss of data. With this da ta collection strategy a temporal resolution of 40 ms is possible. In order to study the mechanical yield of the sample, a bridge-type strain gauge is used which reveals the sample loading. An electronic trigger mechanism pro vides accurate synchronization of the x-ray data, sample video data, sample loading information and controls the onset of deformation. Two experiments are highlighted showing the drawing of polyethylene at an overall rate of approximate to 10 s(-1). By analysis of the sample video data it is possibl e to correlate the SAXS and WAXS data with specific points upon the true st ress-strain curve. This novel system is shown to be a useful tool for the i nvestigation of the deformation of polymers at rates that are relevant to i ndustrial processing. (C) 1999 American Institute of Physics. [S0034-6748(9 9)00210-5].