{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T10:29:55Z","timestamp":1774607395640,"version":"3.50.1"},"reference-count":59,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2022,3,14]],"date-time":"2022-03-14T00:00:00Z","timestamp":1647216000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>The use of real-time techniques to evaluate the global mixing performance of co-rotating twin-screw extruders is well consolidated, but much less is reported on the specific contribution of individual screw zones. This work uses on-line flow turbidity and birefringence to ascertain the mixing performance of kneading blocks with different geometries. For this purpose, one of the barrel segments of the extruder was modified in order to incorporate four sampling devices and slit dies containing optical windows were attached to them. The experiments consisted in reaching steady extrusion and then adding a small amount of tracer. Upon opening each sampling device, material was laterally detoured from the local screw channel, and its turbidity and birefringence were measured by the optical detector. Residence time distribution curves (RTD) were obtained at various axial positions along three different kneading blocks and under a range of screw speeds. It is hypothesized that K, a parameter related to the area under each RTD curve, is a good indicator of dispersive mixing, whereas variance can be used to assess distributive mixing. The experimental data confirmed that these mixing indices are sensitive to changes in processing conditions, and that they translate the expected behavior of each kneading block geometry.<\/jats:p>","DOI":"10.3390\/polym14061152","type":"journal-article","created":{"date-parts":[[2022,3,15]],"date-time":"2022-03-15T02:56:20Z","timestamp":1647312980000},"page":"1152","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5560-4421","authenticated-orcid":false,"given":"Felipe","family":"Bernardo","sequence":"first","affiliation":[{"name":"Graduate Program in Materials Science and Engineering, Federal University of S\u00e3o Carlos, Rod. Washington Luiz, km 235 SP-310, S\u00e3o Carlos 13565-905, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0790-5801","authenticated-orcid":false,"given":"Jos\u00e9 A.","family":"Covas","sequence":"additional","affiliation":[{"name":"Institute for Polymers and Composites (IPC), University of Minho, Campus de Azur\u00e9m, 4800-058 Guimar\u00e3es, Portugal"}]},{"given":"Sebasti\u00e3o V.","family":"Canevarolo","sequence":"additional","affiliation":[{"name":"Department of Materials Engineering, Federal University of S\u00e3o Carlos, Rod. Washington Luiz, km 235 SP-310, S\u00e3o Carlos 13565-905, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Manas-Zloczower, I. (2009). Mixing and Compounding of Polymers: Theory and Practice, Carl Hanser Verlag GmbH & Co.. [2nd ed.].","DOI":"10.3139\/9783446433717.fm"},{"key":"ref_2","unstructured":"Tadmor, Z., and Gogos, C.G. (2006). 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