Nanomechanics of advanced polymer fibres

The micro/nano-structural evolution before and after tensile/compressive loading, fatigue and ultimately, failure has been studied by Raman (and IR) microspectroscopy for PBO, PET, PA66, PP, silk and hair using three probes: low wavenumber collective modes at <150cm-1 as representative of the crystalline/ordered and amorphous chains, stretching and bending modes, as representative of the C-C/ C-N polymeric backbone, and localized vibrations (OH, NH) to probe the inter-macromolecule segment distance. Wavenumber and bandwidth distribution across fibre diameters reveal different types of skin/core heterogeneity. The in situ analysis at different strain/pressure levels shows that amorphous chains in the fibre accommodate the stress differently. The post mortem analysis shows that amorphous domains can be higly stressed during the failure and remnant stress can be measured.