Structural differences between two commercial poly(p-phenyleneterephthalamide) (Kevlar) fibres were studied with scanning electron microscopy and wide angle X-ray scattering. Compared with Kevlar 49, fibres of Kevlar 149 had higher crystallite orientation, larger crystallite size and/or reduced crystalline disorder, and did not display the 300-500 nm axially periodic, pleated sheet structure of Kevlar 49. The high tensile modulus of Kevlar 149 (179 GPa), which is 80-90% of the theoretically predicted value, is attributed to the permanent 'straightening' of the pleated sheet structure associated with increased orientation and improved crystallite ordering.
|Original language||English (US)|
|Number of pages||4|
|Journal||Polymer communications Guildford|
|State||Published - Jan 1 1989|
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