{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T15:12:50Z","timestamp":1788880370704,"version":"build-2803163510"},"reference-count":47,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T00:00:00Z","timestamp":1788825600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Lee-Ming Institute of Technology"},{"id":[{"id":"https:\/\/ror.org\/00k2r9g11","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>A series of polyurethane (PU) nanocomposites incorporating 4,4\u2032-bis(hydroxymethyl)-2,2\u2032-bipyridine (BBD) as a chain extender and a commercially supplied graphene\/zinc oxide (G\/ZnO) hybrid filler were successfully synthesized. The effects of G\/ZnO loading (0\u20132.0 wt.%) on the structural, thermal, mechanical, surface-wettability, and antibacterial properties of the nanocomposites were systematically investigated. Fourier-transform infrared spectroscopy confirmed the formation of the polyurethane structure and revealed changes in characteristic absorption bands following G\/ZnO incorporation. Morphological observation of the pristine G\/ZnO hybrid filler revealed an irregular and aggregated morphology, while X-ray diffraction confirmed the presence of crystalline ZnO. Energy-dispersive X-ray spectroscopy and elemental mapping showed Zn-containing regions within the examined areas of the G\/ZnO-containing PU samples. X-ray photoelectron spectroscopy further confirmed the surface presence of Zn-containing species, with the Zn atomic concentration increasing from 0 at.% in PU-01 to 0.82 at.% in PU-04. Thermogravimetric analysis showed modest changes in thermal decomposition behavior with increasing G\/ZnO loading, while differential scanning calorimetry and dynamic mechanical analysis revealed shifts in glass-transition and relaxation behavior, consistent with changes in polymer-chain mobility and the local interfacial environment. The tensile strength increased from 2.68 MPa for neat PU to 11.76 MPa for the nanocomposite containing 2.0 wt.% G\/ZnO, accompanied by an increase in Young\u2019s modulus. The water contact angle increased from approximately 68\u00b0 to 89\u00b0, indicating reduced apparent surface wettability with increasing G\/ZnO loading. The nanocomposites also exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus, with antibacterial efficiencies exceeding 95% at higher G\/ZnO loadings. Overall, the incorporation of the commercial G\/ZnO hybrid filler was associated with changes in the thermal, mechanical, surface, and antibacterial properties of the BBD-containing PU system. Because separate PU systems without BBD and individual graphene- and ZnO-containing controls were not included, the individual contributions of BBD, graphene, and ZnO, as well as any synergistic effect between graphene and ZnO, cannot be established from the present results. Further studies addressing filler leaching, long-term antibacterial stability, coating adhesion, environmental durability, and cytocompatibility are required to establish the practical applicability of these materials.<\/jats:p>","DOI":"10.3390\/polym18182191","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T14:55:46Z","timestamp":1788879346000},"page":"2191","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Enhanced Multifunctional Properties of Bipyridyl-Containing Polyurethane Nanocomposites Reinforced with Graphene\/ZnO Hybrid Fillers"],"prefix":"10.3390","volume":"18","author":[{"given":"Jing-Lun","family":"Chen","sequence":"first","affiliation":[{"name":"Graduate School of Fabric Technology Management, Lee-Ming Institute of Technology, Taipei 243083, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Yun-Shao","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Applied Cosmetology, Lee-Ming Institute of Technology, Taipei 243083, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Wen-Chin","family":"Tsen","sequence":"additional","affiliation":[{"name":"Graduate School of Fabric Technology Management, Lee-Ming Institute of Technology, Taipei 243083, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2693-1028","authenticated-orcid":false,"given":"Chi-Hui","family":"Tsou","sequence":"additional","affiliation":[{"name":"School of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong 643000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6966-7573","authenticated-orcid":false,"given":"Chin-Wen","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Molecular Science and Engineering, Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2023-2178","authenticated-orcid":false,"given":"Maw-Cherng","family":"Suen","sequence":"additional","affiliation":[{"name":"Graduate School of Fabric Technology Management, Lee-Ming Institute of Technology, Taipei 243083, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"114453","DOI":"10.1039\/C6RA14525F","article-title":"Polyurethane types, synthesis and applications\u2014A review","volume":"6","author":"Akindoyo","year":"2016","journal-title":"RSC Adv."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1157","DOI":"10.1002\/pi.6441","article-title":"Polyurethane foam materials and their industrial applications","volume":"71","author":"Ates","year":"2022","journal-title":"Polym. 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