SEM images of fractured surfaces and stress?strain curves for the MFCs. I: first yield point, II: second yield point.1 PLA microfibrils were produced by multistage stretching extrusion system2 Two distinct yield points exhibited on the tress?strain curves3 The double yielding behavior may be attributed to the PLA microfibrils4 Equatorial streak scattering became stronger with increase in PLA microfibrillar contentIn situ microfibrillar composites (MFCs), with polyolefin elastomer as matrix and poly(lactic acid) (PLA) as dispersed phase, were successfully prepared using multistage stretching extrusion system. Interestingly, a peculiar phenomenon of double yielding was observed on the stress?strain curves of MFCs under tensile loading for the first time. The MFCs with 20?wt% PLA microfibrils exhibited two distinct yield points, and a pronounced hump appeared on the stress?strain curve of PLA?20. Two?dimensional small?angle X?ray scattering analyses showed that the equatorial streak scattering became stronger with increase in PLA microfibrillar content; the meridional scattering trace became stronger with increase in tensile strain for PLA?20. The rheological analysis showed that the G? of PLA?20 had a plateau in the low frequency region and did not depend on frequency changes.
» Author: Jing Sun,
» Reference: doi:10.1002/pen.25451
» Publication Date: 27/06/2020
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