Simultaneous WAXS/SAXS study on semi-crystalline Poly(ethylene furanoate) under uniaxial stretching
Yimin Mao, David G. Bucknall, Robert M. Kriegel
Index: 10.1016/j.polymer.2018.04.018
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Abstract
A time-resolved study of uniaxial deformation processes of semi-crystalline poly (ethylene furanoate) (PEF) at 200 °C°C was carried out using synchrotron simultaneous wide- and small-angle X-ray scattering (WAXS/SAXS) techniques. The stretching was able to dissociate existing lamellar crystal assemblies in the early stages of stretching (for strains less than ≈≈ 0.6), causing a slight decrease of crystallinity, and an increase of inter-lamellar distance. As stretching proceeded, an increase of crystallinity and at the same time a decrease of inter-lamellar distance was observed. Preferred orientation behavior in the early stages of stretching was complex, but could be approximated using oblique b-axis orientation associated with intra-lamellar slip along the [100] plane. In the late stages of deformation, new lamellar crystals were formed with their normal, i.e. , the cc -axis direction, parallel to the stretching direction.