Metal‐organic framework MIL‐53 (Fe)@C/graphite carbon nitride hybrids with enhanced thermal stability, flame retardancy, and smoke suppression for unsaturated polyester resin

J of Applied Polymer Sci

Yuan

et al. 2021

Self Cite

Phosphorus and silicon co-doped graphitic carbon nitride (PSiCN) was synthesized by inducing the polycondensation reaction of melamine, diammonium hydrogen phosphate, and silicic acid. The structure and thermal properties of PSiCN were characterized. With the incorporation of 2 wt% of PSiCN and 8 wt% of ammonium polyphosphate (APP), EP/2PSiCN-8APP composite exhibited a limiting oxygen index value of 29.0% and passed a UL-94V-0 rating, which reached the refractory level. The thermogravimetric analysis confirmed that the addition of PSiCN and APP improved the thermal stability of the composites. The cone calorimetry test (CCT) revealed that the peak of heat release rate, total heat release, the peak of smoke production rate and total smoke production of EP/2PSiCN-8APP composite was reduced by 71.1%, 53.5%, 65.4%, and 53.5%, respectively, compared with pure EP. Furthermore, the residues after CCT were evaluated by scanning electron microscopy, laser Raman spectroscopy and Fourier transform infrared spectroscopy, and the flame retardant mechanism of EP/2PSiCN-8APP composite was proposed. Finally, the parallel arrangement of the aromatic ring and the surface of the PSiCN and the synergistic effect of the P/N/Si multi-element resulted in EP/2PSiCN-8APP with excellent mechanical properties.

Section: Characterization Of Psicnmentioning

confidence: 91%

Synthesis of phosphorus and silicon co‐doped graphitic carbon nitride and its combination with ammonium polyphosphate to enhance the flame retardancy of epoxy resin

Zhang

J of Applied Polymer Sci

Yuan

et al. 2021

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“…Unsaturated polyester resin (UPR) is widely used in transportation, chemical production, construction, sports, clothing, and other fields because of its convenient processing, low raw material cost, good water and chemical resistance, etc . However, wider application of UPR is limited due to its extremely flammable properties during combustion.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of diatomite‐based microencapsulated flame retardant and its improved fire safety of unsaturated polyester resin

Yuan

Polymers for Advanced Techs

et al. 2019

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To achive excellent fire resistance, new microcapsule flame retardants (DMCAD and DMPPD) were prepared using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide combined with melamine cyanurate or melamine polyphosphate as the shell material and diatomite as the core material. The successful assembly of DMCAD and DMPPD was detailed characterized by Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Meanwhile, the flame retardancy and thermal stability of the unsaturated polyester resin (UPR)/DMCAD and UPR/DMPPD composites were also studied. The addition of DMCAD and DMPPD effectively improves the flame retardance properties of UPR, and the effect of DMPPD was better. The limiting oxygen index (LOI) of UPR/DMPPD-3 increased by 11.6% when compared with that of UPR, and the sample achieved V-0 rating. Moreover, the peak heat release rate (pHRR) and the total heat release (THR) rate of UPR/DMPPD-3 were reduced by 67% and 26%, respectively. Under nitrogen condition and air condition, UPR/DMPPD showed better thermal stability and char-forming ability from the thermogravimetric (TG) results. Residual char of the UPR composites was systematically analyzed with SEM and XPS. Finally, the flame retardant mechanism of DMPPD was proposed. K E Y W O R D S diatomite, flame retardancy, microencapsulation, unsaturated polyester resin 1 | INTRODUCTION Unsaturated polyester resin (UPR) is widely used in transportation,chemical production, construction, sports, clothing, and other fields because of its convenient processing, low raw material cost, good water and chemical resistance, etc. 1-3 However, wider application of UPR is limited due to its extremely flammable properties during combustion. Therefore, improving the flame retardancy of UPR can further expand its application. In the last decades, halogen-based flame retardants have been widely applied but their pollution and toxicity limit their large-scale application. 4 Presently, environmentally halogen-free flame retardants have attracted widespread attention. In particular, the phosphorus and phosphorus-nitrogen containing flame retardants are mainly used as intumescent flame retardants (IFRs), which produce fewer toxic gases and smoke than halogen-based flame retardants. 5,6 Melamine (Mel) and its derivatives are promising candidates, for they are effective, economical, and environmentally friendly. Mel cyanurate (MCA) is a popular Mel-based flame retardant, which has significant advantages for its low cost, high nitrogen content, noncorrosiveness, and nontoxicity. 7 The nitrogen-containing inert gas generated by MCA during combustion can effectively dilute

“…Typically, the integrated intensity ratio of the D and G bands ( I D / I G ) could be used to characterize the graphitization degree of carbon residue. The lower the I D / I G , the higher the degree of graphitization 38,39 . The I D / I G value of pure EP was 3.7, which was the highest of all samples, indicating that the carbon layer of EP was the most unstable.…”

Section: Resultsmentioning

confidence: 92%

Surface modification of cellulose nanocrystal and its applications in flame retardant epoxy resin

Suo

Gao

J of Applied Polymer Sci

et al. 2022

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In this work, surface modification of cellulose nanocrystal (CNC) with diphenyl phosphate and Zn(OAc) 2 Á2H 2 O was prepared by a green method to obtain CNCbased flame retardant CNC@DPP@Zn and then added into epoxy resins (EP). The structure, morphology, and thermal stability of CNC@DPP@Zn were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TG). Flame retardancy and combustion behavior of EP/CNC@DPP@Zn composites were characterized by TG, limiting oxygen index (LOI) test, vertical burning (UL-94) test and cone calorimeter tests (CCT). The results of CCT demonstrated that the peak heat release rate (pHRR), total heat release (THR), and total smoke production (TSP) of EP/8CNC@DPP@Zn composites reduced by 38.3%, 15.5%, and 36.0%, respectively, compared with pure EP. The char residues after CCT were characterized by laser Raman spectroscopy (LRS) and scanning electron microscope (SEM). Finally, the flame retardancy mechanism of CNC@DPP@Zn was proposed.