{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T17:28:08Z","timestamp":1790011688950,"version":"4.0.1"},"reference-count":77,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,21]],"date-time":"2023-07-21T00:00:00Z","timestamp":1689897600000},"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 inefficient reuse and recycling of plastics\u2014and the current surge of medical and take-out food packaging use during the pandemic\u2014have exacerbated the environmental burden. This impels the development of alternative recycling\/upcycling methods to pivot toward circularity. We report the use of the Mannich three-component coupling reaction for the modification of polystyrene (PS) recovered with a 99.1% yield from waste food containers to form functionalized nitrogen and oxygen-rich PS derivatives. A series of functionalized PS with increasing moles of formaldehyde (F) and morpholine (M) (0.5 \u00d7 10\u22122, 1.0 \u00d7 10\u22122, and 2.0 \u00d7 10\u22122 mol) was achieved using a sol\u2013gel-derived Fe-TiO2 catalyst in a solvent-free, microwave-assisted synthesis. Modified polymers were characterized with viscometry, 1H NMR, 13CNMR (DEPT) FTIR, XPS, UV, and TGA. Functionalization scaled with an increasing ratio, validating the 3CR approach. Further functionalization was constrained by a competing oxidative degradation; however, the varying hydrogen bond density due to nitrogen and oxygen-rich species at higher ratios was shown to compensate for molecular weight loss. The integration of the N-cyclic quaternary ammonium cations exhibited the potential of functionalized polymers for ion-exchange membrane applications.<\/jats:p>","DOI":"10.3390\/polym15143108","type":"journal-article","created":{"date-parts":[[2023,7,24]],"date-time":"2023-07-24T01:12:28Z","timestamp":1690161148000},"page":"3108","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Circular Design and Functionalized Upcycling of Waste Commodity Polystyrene via C-H Activation Using Microwave-Assisted Multicomponent Synthesis"],"prefix":"10.3390","volume":"15","author":[{"given":"Shegufta","family":"Shetranjiwalla","sequence":"first","affiliation":[{"name":"School of Science and the Environment, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL A2H 5G4, Canada"},{"name":"Chemistry Department, Trent University, Peterborough, ON K9K 0G2, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Claire","family":"Cislak","sequence":"additional","affiliation":[{"name":"Chemistry Department, Trent University, Peterborough, ON K9K 0G2, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kevin M.","family":"Scotland","sequence":"additional","affiliation":[{"name":"Chemistry Department, Trent University, Peterborough, ON K9K 0G2, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"768","DOI":"10.1126\/science.1260352","article-title":"Plastic waste inputs from land into the ocean","volume":"347","author":"Jambeck","year":"2015","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e1700782","DOI":"10.1126\/sciadv.1700782","article-title":"Production, use, and fate of all plastics ever made","volume":"3","author":"Geyer","year":"2017","journal-title":"Sci. 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