{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,19]],"date-time":"2026-04-19T19:22:21Z","timestamp":1776626541967,"version":"3.51.2"},"reference-count":54,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2022,12,5]],"date-time":"2022-12-05T00:00:00Z","timestamp":1670198400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT-Foundation for Science and Technology","award":["UID\/CTM\/00264\/2021"],"award-info":[{"award-number":["UID\/CTM\/00264\/2021"]}]},{"name":"FCT-Foundation for Science and Technology","award":["UIDB\/00264\/2020"],"award-info":[{"award-number":["UIDB\/00264\/2020"]}]},{"name":"COMPETE and FCT\/MCTES (PIDDAC) co-financed by FEDER through the PT2020 program","award":["UID\/CTM\/00264\/2021"],"award-info":[{"award-number":["UID\/CTM\/00264\/2021"]}]},{"name":"COMPETE and FCT\/MCTES (PIDDAC) co-financed by FEDER through the PT2020 program","award":["UIDB\/00264\/2020"],"award-info":[{"award-number":["UIDB\/00264\/2020"]}]},{"name":"\u201cplurianual\u201d 2020\u20132023","award":["UID\/CTM\/00264\/2021"],"award-info":[{"award-number":["UID\/CTM\/00264\/2021"]}]},{"name":"\u201cplurianual\u201d 2020\u20132023","award":["UIDB\/00264\/2020"],"award-info":[{"award-number":["UIDB\/00264\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Compos. Sci."],"abstract":"<jats:p>In this work, pyrolytically stripped carbon nanofiber (CNF) polypropylene (PP) composites were synthesized following a scalable melt-mixing method, and the effects of CNF weight concentrations on the electrical conductivity, dielectric permittivity, electrical modulus and electrical impedance of PP\/CNF composites were studied. Quite unexpectedly, the electrical conductivity of PP\/CNF composites improved only slightly as the incorporation of CNFs was raised, yielding a maximum of ~10\u221210 S m\u22121 for PP\/CNF 5 wt. % composites. The increase corresponded to a gradual improvement of the dielectric constant up to a maximum of ~9 for PP\/CNF 5 wt. % composites at 1 MHz, which was attributed to the raise of interface polarization effect. Moreover, the Cole\u2013Cole model was used to analyze the effects of CNF concentrations on the dielectric relaxation of PP\/CNF composites, from which was deduced that the incorporation of CNFs increases their dielectric strength and relaxation times. The analysis gathered here aims to provide a better insight into the enhanced dielectric properties observed in low-conducting polymer composites filled with CNFs.<\/jats:p>","DOI":"10.3390\/jcs6120368","type":"journal-article","created":{"date-parts":[[2022,12,5]],"date-time":"2022-12-05T04:10:02Z","timestamp":1670213402000},"page":"368","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Dielectric Spectroscopy of Melt-Mixed Polypropylene and Pyrolytically Stripped Carbon Nanofiber Composites"],"prefix":"10.3390","volume":"6","author":[{"given":"Zineb","family":"Samir","sequence":"first","affiliation":[{"name":"Laboratory of Material Physics and Subatomic, Faculty of Sciences, Ibn Tofail University, BP 242, Kenitra 14000, Morocco"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4688-5794","authenticated-orcid":false,"given":"Antonio J.","family":"Paleo","sequence":"additional","affiliation":[{"name":"2C2T-Centre for Textile Science and Technology, University of Minho, Campus de Azur\u00e9m, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6585-2728","authenticated-orcid":false,"given":"Najoia","family":"Aribou","sequence":"additional","affiliation":[{"name":"Laboratory of Material Physics and Subatomic, Faculty of Sciences, Ibn Tofail University, BP 242, Kenitra 14000, Morocco"}]},{"given":"Yassine","family":"Nioua","sequence":"additional","affiliation":[{"name":"Laboratory of Material Physics and Subatomic, Faculty of Sciences, Ibn Tofail University, BP 242, Kenitra 14000, Morocco"}]},{"given":"Jaime Oliveira","family":"da Silva","sequence":"additional","affiliation":[{"name":"CFisUC, Department of Physics, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugal"}]},{"given":"Maria F.","family":"Cerqueira","sequence":"additional","affiliation":[{"name":"INL\u2014International Iberian Nanotechnology Laboratory, Av. Mestre. Jose Veiga, 4715-330 Braga, Portugal"},{"name":"CFUM\u2014Center of Physics of the University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4659-7503","authenticated-orcid":false,"given":"Joaquim Agostinho","family":"Moreira","sequence":"additional","affiliation":[{"name":"IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de F\u00edsica e Astronomia, Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7786-0645","authenticated-orcid":false,"given":"Mohammed E.","family":"Achour","sequence":"additional","affiliation":[{"name":"Laboratory of Material Physics and Subatomic, Faculty of Sciences, Ibn Tofail University, BP 242, Kenitra 14000, Morocco"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1573","DOI":"10.1002\/(SICI)1097-4628(19990620)72:12<1573::AID-APP10>3.0.CO;2-6","article-title":"Electrical properties of composites in the vicinity of the percolation threshold","volume":"72","author":"Foulger","year":"1999","journal-title":"J. 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