{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T14:29:07Z","timestamp":1788791347157,"version":"build-2803163510"},"reference-count":29,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2023,4,17]],"date-time":"2023-04-17T00:00:00Z","timestamp":1681689600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"General Project of Science and Technology Plan of Beijing Municipal Commission of Education","award":["NO. KM202010011001"],"award-info":[{"award-number":["NO. KM202010011001"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>This work investigated the effect of different valence states of phosphorus-containing compounds on thermal decomposition and flame retardancy of polyethylene terephthalate (PET). Three polyphosphates\u2014PBPP with +3-valence P, PBDP with +5-valence P and PBPDP with both +3\/+5-valence P\u2014were synthesized. The combustion behaviors of flame-retardant PET were studied and the structure\u2013property relationships between the phosphorus-based structures with different valence states and flame-retardant properties were further explored. It was found that phosphorus valence states significantly affected the flame-retardant modes of action of polyphosphate in PET. For the phosphorus structures with +3-valence, more phosphorus-containing fragments were released in the gas phase, inhibiting polymer chain decomposition reactions; by contrast, those with +5-valence phosphorus retained more P in the condensed phase, promoting the formation of more P-rich char layers. It is worth noting that the polyphosphate containing both +3\/+5-valence phosphorous tended to combine the advantage of phosphorus structures with two valence states and balance the flame-retardant effect in the gas phase and condensed phase. These results contribute to guiding the design of specified phosphorus-based structures of flame-retardant compounds in polymer materials.<\/jats:p>","DOI":"10.3390\/polym15081917","type":"journal-article","created":{"date-parts":[[2023,4,18]],"date-time":"2023-04-18T01:36:45Z","timestamp":1681781805000},"page":"1917","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["How Do Phosphorus Compounds with Different Valence States Affect the Flame Retardancy of PET?"],"prefix":"10.3390","volume":"15","author":[{"given":"Siheng","family":"Zhao","sequence":"first","affiliation":[{"name":"School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China"},{"name":"Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China"},{"name":"China Light Industry Engineering Technology Research Center of Advanced Flame Retardants, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9114-4015","authenticated-orcid":false,"given":"Bo","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China"},{"name":"Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China"},{"name":"China Light Industry Engineering Technology Research Center of Advanced Flame Retardants, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hao","family":"Shan","sequence":"additional","affiliation":[{"name":"School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China"},{"name":"Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China"},{"name":"China Light Industry Engineering Technology Research Center of Advanced Flame Retardants, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qinglei","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China"},{"name":"Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China"},{"name":"China Light Industry Engineering Technology Research Center of Advanced Flame Retardants, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangdong","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China"},{"name":"Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China"},{"name":"China Light Industry Engineering Technology Research Center of Advanced Flame Retardants, Beijing 100048, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.pnsc.2020.01.018","article-title":"Synthesis, characterization of a DOPO-based polymeric flame retardant and its application in polyethylene terephthalate","volume":"30","author":"Ao","year":"2020","journal-title":"Prog. Nat. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6541","DOI":"10.1002\/slct.202100708","article-title":"Phosphorus Ester Containing Mesoporous Silica as Novel High-Effective Flame Retardant in Polyurethane and Polyester Coatings","volume":"6","author":"Aytan","year":"2021","journal-title":"Chemistryselect"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"9349","DOI":"10.1021\/acsami.5b02141","article-title":"Permanent Flame Retardant Finishing of Textiles by Allyl-Functionalized Polyphosphazenes","volume":"7","author":"Knittel","year":"2015","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1909","DOI":"10.1016\/j.eurpolymj.2004.03.013","article-title":"A novel non-dripping oligomeric flame retardant for polyethylene terephthalate","volume":"40","author":"Ban","year":"2004","journal-title":"Eur. Polym. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1016\/j.compscitech.2012.01.008","article-title":"PET in situ composites improved both flame retardancy and mechanical properties by phosphorus-containing thermotropic liquid crystalline copolyester with aromatic ether moiety","volume":"72","author":"Chen","year":"2012","journal-title":"Compos. Sci. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4746","DOI":"10.3390\/ma3104746","article-title":"Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers","volume":"3","author":"Chen","year":"2010","journal-title":"Materials"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1002\/vnl.21688","article-title":"Synthesize and Characterization of Flame Retardant Copolyesters PET\/Phosphorus Compound","volume":"25","author":"Abbasi","year":"2019","journal-title":"J. Vinyl Addit. Technol."},{"key":"ref_8","first-page":"1","article-title":"A review on flame retardant technology in China. Part I: Development of flame retardants","volume":"21","author":"Li","year":"2009","journal-title":"Polym. Adv. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"108349","DOI":"10.1016\/j.compositesb.2020.108349","article-title":"Rationally designed zinc borate@ZIF-8 core-shell nanorods for curing epoxy resins along with low flammability and high mechanical property","volume":"200","author":"Jian","year":"2020","journal-title":"Compos. Part B Eng."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"42016","DOI":"10.1002\/app.42016","article-title":"Flame retardancy and mechanical properties of pet-based composites containing phosphorus and boron-based additives","volume":"132","author":"Kilinc","year":"2015","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"45246","DOI":"10.1002\/app.45246","article-title":"An effective flame retardant for poly(ethylene terephthalate) synthesized by phosphaphenanthrene and cyclotriphosphazene","volume":"134","author":"Fang","year":"2017","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1210","DOI":"10.1002\/pi.6403","article-title":"Effect of two boron compounds on smoke-suppression and flame-retardant properties for rigid polyurethane foams","volume":"71","author":"Xu","year":"2022","journal-title":"Polym. Int."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"109281","DOI":"10.1016\/j.polymdegradstab.2020.109281","article-title":"Enhancement of the intumescent flame retardant efficiency in polypropylene by synergistic charring effect of a hypophosphite\/cyclotetrasiloxane bi-group compound","volume":"181","author":"Xu","year":"2020","journal-title":"Polym. Degrad. Stab."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"48699","DOI":"10.1002\/app.48699","article-title":"Flame retardant application of a hypophosphite\/cyclotetrasiloxane bigroup compound on polycarbonate","volume":"137","author":"Shao","year":"2020","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"8495","DOI":"10.1016\/j.polymer.2006.10.022","article-title":"Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites","volume":"47","author":"Braun","year":"2006","journal-title":"Polymer"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e52837","DOI":"10.1002\/app.52837","article-title":"A double-click strategy for the synthesis of P and N-containing hydrolytically stable reactive flame retardant for photocurable networks","volume":"139","author":"Ozukanar","year":"2022","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Bo, X., Zhao, S.H., Shan, H., Wei, S.M., and Zhang, Q.L. (2022). A Sulfur-Containing Polyphosphonate Flame Retardant for Polyethylene Terephthalate. Combust. Sci. Technol.","DOI":"10.1080\/00102202.2022.2109153"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"131634","DOI":"10.1016\/j.cej.2021.131634","article-title":"Construction of hierarchical Ti3C2TX@PHbP-PHC architecture with enhanced free-radical quenching capability: Effective reinforcement and fire safety performance in bismaleimide resin","volume":"427","author":"Zhou","year":"2022","journal-title":"Chem. Eng. J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3037","DOI":"10.1016\/j.polymer.2009.04.026","article-title":"Transesterification-controlled compatibility and microfibrillation in PC\u2013ABS composites reinforced by phosphorus-containing thermotropic liquid crystalline polyester","volume":"50","author":"Huang","year":"2009","journal-title":"Polymer"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.cej.2018.03.013","article-title":"Persistently flame-retardant flexible polyurethane foams by a novel phosphorus-containing polyol","volume":"343","author":"Rao","year":"2018","journal-title":"Chem. Eng. J."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"124106","DOI":"10.1016\/j.jhazmat.2020.124106","article-title":"Barrier function of graphene for suppressing the smoke toxicity of polymer\/black phosphorous nanocomposites with mechanism change","volume":"404","author":"Cai","year":"2021","journal-title":"J. Hazard. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1016\/j.conbuildmat.2019.01.097","article-title":"Facile preparation of slag or fly ash geopolymer composite coatings with flame resistance","volume":"203","author":"Wang","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3316","DOI":"10.1002\/pat.5055","article-title":"Impact on flame retardancy and degradation behavior of intumescent flame-retardant EP composites by a hyperbranched triazine-based charring agent","volume":"31","author":"Liu","year":"2020","journal-title":"Polym. Adv. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1016\/j.jaap.2018.06.013","article-title":"Synthesis and characterization of a novel organic-inorganic hybrid char-forming agent and its flame-retardant application in polypropylene composites","volume":"134","author":"Xu","year":"2018","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3171","DOI":"10.1016\/j.eurpolymj.2013.06.009","article-title":"Influence of oxidation state of phosphorus on the thermal and flammability of polyurea and epoxy resin","volume":"49","author":"Mariappan","year":"2013","journal-title":"Eur. Polym. J."},{"key":"ref_26","first-page":"150","article-title":"Boron\/phosphorus-containing flame-retardant photocurable coatings","volume":"2015","author":"Kahraman","year":"2015","journal-title":"RSC Smart Mater."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"109516","DOI":"10.1016\/j.polymdegradstab.2021.109516","article-title":"A phosphorous-based bi-functional flame retardant for rigid polyurethane foam","volume":"186","author":"Wang","year":"2021","journal-title":"Polym. Degrad. Stab."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Xu, B., Liu, Y., Wei, S., Zhao, S., Qian, L., Chen, Y., Shan, H., and Zhang, Q. (2022). A Phosphorous-Based Bi-Functional Flame Retardant Based on Phosphaphenanthrene and Aluminum Hypophosphite for an Epoxy Thermoset. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms231911256"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Denis, M., Coste, G., Sonnier, R., Caillol, S., and Negrell, C. (2023). Influence of Phosphorus Structures and Their Oxidation States on Flame-Retardant Properties of Polyhydroxyurethanes. Molecules, 28.","DOI":"10.3390\/molecules28020611"}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/8\/1917\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:17:29Z","timestamp":1760123849000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/8\/1917"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,4,17]]},"references-count":29,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2023,4]]}},"alternative-id":["polym15081917"],"URL":"https:\/\/doi.org\/10.3390\/polym15081917","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,4,17]]}}}