Accessible Requires Authentication Published by De Gruyter September 15, 2021

Fiber Length Distribution in Twin-Screw Extrusion of Fiber-Reinforced Polymer Composites: A Comparison between Shear and Extensional Mixing

M. Guo, X. Li and J. M. Maia


New extensional mixing elements (EME) for twin-screw extrusion were applied to compound glass fibers (GF), carbon fibers (CF) or polyethylene terephthalate fibers (PETF) reinforced polymer composites with polymer matrix of polypropylene (PP) or polyethylene oxide (PEO) and the resulting fiber degradation upon processing was evaluated and compared with compounding via shear flow-dominated kneading blocks (KB). Composites structures were characterized in terms of fiber length and distribution, and cumulative length ratio, at five locations along the mixing zone. Although significant fiber breakage was achieved for both configurations, it was markedly lower in composites processed using the EME, because whereas the high shear stress kneading motion in the KB degrades fibers significantly, fiber breakup is significantly minimized by the alignment induced by the EME prior to flow in the high-stress regions.

João M. Maia, Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106-7202, USA


The authors thank MiniFIBERS for kindly gifting the PETF. The authors would also like acknowledge Akash Agrawal for the help with the extrusion.


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Received: 2020-04-22
Accepted: 2020-06-14
Published Online: 2021-09-15
Published in Print: 2021-09-27

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