{"title":"Methylcellulose-based composite hydrogels with high water retention and strong flame retardancy","authors":"Mengru Wei , Shikuan Xu , Fengmei Ding , Yanjun Xing","doi":"10.1016/j.porgcoat.2025.109681","DOIUrl":null,"url":null,"abstract":"<div><div>In this study, a green flame-retardant thermo-sensitive hydrogel was developed, comprising methyl cellulose (MC) as the carrier, a phytic acid (PA)-urea (U) composite (PAU) as the flame retardant and calcium cation (Ca<sup>2+</sup>) as the water absorbent. When applied to fabrics, the hydrogel undergoes a phase transition upon exposure to high temperatures, forming a robust barrier that significantly enhances flame retardancy. The samples were characterized using Fourier-transform infrared spectroscopy (FTIR), rheology, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The water absorption and retention properties of the MC/PAU/Ca coating were also evaluated, demonstrating superior absorbency, water retention, and thermal stability, which collectively contribute to improved flame retardancy. Compared with the untreated fabric, the MC/PAU/Ca flame-retardant coated sample exhibited a limiting oxygen index (LOI) value of 44.8 ± 1.5 %, and vertical flame testing (VFT) confirmed a UL-94 V-0 rating. The flame-retardant mechanism of coating in the gas phase and the condensed phase were effectively investigated by the FTIR of char residue and Thermogravimetric analysis-infrared spectrometry (TG-IR) analysis. During combustion, the coating generated a dense char layer enriched with phosphorus (P), nitrogen (N), and calcium (Ca), along with the non-flammable gases, which synergistically acted as an effective flame retardant mechanism. Overall, the MC/PAU/Ca hydrogel represents a promising green flame-retardant coating for flammable materials.</div></div>","PeriodicalId":20834,"journal":{"name":"Progress in Organic Coatings","volume":"210 ","pages":"Article 109681"},"PeriodicalIF":7.3000,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Progress in Organic Coatings","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0300944025006307","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
In this study, a green flame-retardant thermo-sensitive hydrogel was developed, comprising methyl cellulose (MC) as the carrier, a phytic acid (PA)-urea (U) composite (PAU) as the flame retardant and calcium cation (Ca2+) as the water absorbent. When applied to fabrics, the hydrogel undergoes a phase transition upon exposure to high temperatures, forming a robust barrier that significantly enhances flame retardancy. The samples were characterized using Fourier-transform infrared spectroscopy (FTIR), rheology, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The water absorption and retention properties of the MC/PAU/Ca coating were also evaluated, demonstrating superior absorbency, water retention, and thermal stability, which collectively contribute to improved flame retardancy. Compared with the untreated fabric, the MC/PAU/Ca flame-retardant coated sample exhibited a limiting oxygen index (LOI) value of 44.8 ± 1.5 %, and vertical flame testing (VFT) confirmed a UL-94 V-0 rating. The flame-retardant mechanism of coating in the gas phase and the condensed phase were effectively investigated by the FTIR of char residue and Thermogravimetric analysis-infrared spectrometry (TG-IR) analysis. During combustion, the coating generated a dense char layer enriched with phosphorus (P), nitrogen (N), and calcium (Ca), along with the non-flammable gases, which synergistically acted as an effective flame retardant mechanism. Overall, the MC/PAU/Ca hydrogel represents a promising green flame-retardant coating for flammable materials.
期刊介绍:
The aim of this international journal is to analyse and publicise the progress and current state of knowledge in the field of organic coatings and related materials. The Editors and the Editorial Board members will solicit both review and research papers from academic and industrial scientists who are actively engaged in research and development or, in the case of review papers, have extensive experience in the subject to be reviewed. Unsolicited manuscripts will be accepted if they meet the journal''s requirements. The journal publishes papers dealing with such subjects as:
• Chemical, physical and technological properties of organic coatings and related materials
• Problems and methods of preparation, manufacture and application of these materials
• Performance, testing and analysis.