Single-stage synthesis of phosphazene-containing epoxy oligomers

Сиротин, И. С.; Bilichenko, Yu. V.; Brigadnov, K. A.; Киреев, В. В.; Prudskov, B. M.; Борисов, Р. С.

doi:10.1134/s1560090414040113

Cited by 18 publications

(15 citation statements)

References 14 publications

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“…Among different phosphorus flame retardants, phosphazenes are of particular interest due to the synergistic effect of phosphorus and nitrogen atoms acting simultaneously [4,5,6,7,8,9,13,14,15,16,17,18,19,20,21,22]. Fireproof epoxy compositions based on phosphazenes were prepared, of which resistance to combustion was achieved by the addition of small amounts of phosphazene modifiers [4,5], e.g., hexa(4-maleimidophenoxy)cyclotriphosphazene (9 wt %) [13] or hexa-[4-(hydroxyanilinephosphaphenanthrenemethyl)-phenoxy]cyclotriphosphazene (10 wt %) [9].…”

Section: Introductionmentioning

confidence: 99%

Curing of Epoxy Resin DER-331 by Hexakis(4-acetamidophenoxy)cyclotriphosphazene and Properties of the Prepared Composition

et al. 2019

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The method of optical wedge revealed that the optimum temperature for compatibility of hexakis(4-acetamidophenoxy)cyclotriphosphazene (ACP) and DER-331 epoxy resin is in the range of 220–260 °C. The interdiffusion time of components at these temperatures is about 30 min. The TGA and differential scanning calorimetry (DSC) methods revealed the curing temperature of 280 °С for this composition. IR spectroscopy confirmed that the reaction between the resin and ACP is completed within 10 min. According to the DSC data, a glass transition temperature of 130 °С was estimated for the cured resin. Combustion test UL-94 demonstrated that the obtained material can be assigned to the fireproof category of V-0. Burning droplets were not formed during the burning. The coke formed during the combustion of samples possessed a dense and porous structure. The shape of pores is closed, while their size is in the range of 0.2–200 µm.

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Section: Introductionmentioning

confidence: 99%

Curing of Epoxy Resin DER-331 by Hexakis(4-acetamidophenoxy)cyclotriphosphazene and Properties of the Prepared Composition

et al. 2019

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“…Previously, using the example of a bisphenol-A based PEO, it was shown that to eliminate gelation in highly functional A 2 + B 6 systems (diphenol:HCP), it is necessary to use diphenol in an amount that provides at least a twofold excess of OH-groups relative to P–Cl bonds [69,70]. …”

Section: Resultsmentioning

confidence: 99%

“…As in the case of bisphenol A based epoxyphosphazene oligomers [69,70], the PERO phosphazene fraction mainly contains compounds with 1–2 unsubstituted chlorine atoms in the triphosphazene cycle. This is indicated by the presence in the 31 P spectra (Figure 2) of signals of phosphorus atoms belonging to tetra- (AB 2 system with cis-trans isomerism, δ P = 19.4 ppm (dd) and 4.2 ppm (tt)) and penta-substituted (AB 2 system, δ P = 21.2 ppm (t) and 6.2 (d)) trimeric cycles.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of Resorcinol-Based Phosphazene-Containing Epoxy Oligomers

et al. 2019

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Phosphazene-containing epoxy-resorcinol oligomers (PERO) are synthesized in one stage with the direct interaction of hexachlorocyclotriphosphazene (HCP), resorcinol, and epichlorohydrin in the presence of solid NaOH. Depending on the initial ratio of HCP:resorcinol, PERO contains from 20 to 50 wt.% phosphazene component (2.0–4.8% of phosphorus) and have an epoxy group content up to 30 %. Products are characterized using 1H and 31P NMR spectroscopy, MALDI-TOF mass spectrometry, and elemental analysis. According to mass spectrometry, the phosphazene fractions of PERO include up to 30 individual compounds with a predominance of cyclotriphosphazenes with one unsubstituted chlorine atom and four or five glycidyl groups. PERO has a lower viscosity in comparison with similar resins based on bisphenol A, which can simplify their use as a binder for polymer composites, adhesives, and paints.

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“…Therefore, epoxy resins modified with epoxycyclophosphazenes appear to be a promising base for halogen-free binders for critical use. Recently, scalable methods for epoxycyclophosphazene synthesis have appeared [ 6 , 16 , 18 ], which make it possible to believe that they may become available starting components in the market for composite manufacture.…”

Section: Introductionmentioning

confidence: 99%

Isothermal Kinetics of Epoxyphosphazene Cure

et al. 2021

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The influence of epoxycyclophosphazene modifier on the process of epoxy-amine curing was studied by differential scanning calorimetry (DSC). The study revealed that the curing process of epoxyphosphazene binders with 4′4′diaminodiphenylsulfone (DDS) provides more complete curing of the formulations in comparison with ones applying low molecular-weight polyamide curing agent (L-20). The isothermal kinetics of curing was described by means of model fitting and the isoconversional approach (Friedman method). Accurate n-order approximation was obtained for all systems under study. In particular, the 2-order equation fits well with the main part of curing excluding high degrees of conversion. The process of curing could be distinguished into three zones. The transition from zone 2 to zone 3 correlates with gelation. According to the isoconversional analysis by Friedman method, the diffusion-controlled mechanism is found at final stage of curing.

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Single-stage synthesis of phosphazene-containing epoxy oligomers

Cited by 18 publications

References 14 publications

Curing of Epoxy Resin DER-331 by Hexakis(4-acetamidophenoxy)cyclotriphosphazene and Properties of the Prepared Composition

Curing of Epoxy Resin DER-331 by Hexakis(4-acetamidophenoxy)cyclotriphosphazene and Properties of the Prepared Composition

Synthesis of Resorcinol-Based Phosphazene-Containing Epoxy Oligomers

Isothermal Kinetics of Epoxyphosphazene Cure

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