Mixed hydroxy-aryloxy cyclotriphosphazenes have been synthesized via the interaction of hexachlorocyclotriphosphazene with a mixture of 4-allyl-2-methoxyphenol and diphenylolpropane (molar ratio 3.5 : 7.0). Their subsequent epoxidation with epichlorohydrin has afforded phosphazene-containing oligoepoxides with the phosphazene fraction of 50%. Optimal conditions for the synthesis of the composition-uniform phosphazene-containing oligoepoxides bearing one, two, and three epoxide groups in the phosphazene cycle have been elaborated. Such phosphazene-containing oligoepoxides can be cured with the curing agents common for the epoxy resins, to afford self-extinguishing compositions.

Oligomeric aryloxycyclotriphosphazenes with mixed functional groups are synthesized by the interaction of hexachlorocyclotriphosphazene and two phenols, methyl-4-hydroxybenzoate (paraben) and 4‑allyl-2-methoxyphenol (eugenol), at different order of their introduction into the reaction mixture. The hydrolysis of ester groups of aryloxycyclotriphosphazenes yields corresponding carboxyphenoxycyclophosphazenes, and the oxidation of their allyl groups by m-chloroperbenzoic acid affords epoxy derivatives. Optimal conditions for the indicated transformations are determined, and structure of the resulting oligomers is studied by 1Н and 31Р NMR spectroscopy and MALDI-TOF mass spectrometry.

Carboxyl-containing aryloxycyclotriphosphazene (I) has been used for curing the ED-20 epoxy resin or a phosphazene-containing epoxy oligomer. In the case of ED-20, curing occurs in the range of 125‒220°C and is accompanied by an exothermic effect that increases from 26 to 50 J/g with an increase in the amount of aryloxycyclotriphosphazene (I) from 25 to 50%. The curing of the phosphazene-containing epoxy oligomer occurs in the temperature range of 140–240°C and is accompanied by an endothermic effect (−Δ H = 6.5–6.8 J/g). Cured compositions based on ED-20 + I are self-extinguishing (flammability class V‑1 according to UL-94), and phosphazene-containing epoxy oligomer + I compositions are noncombustible (class V-0 according to UL-94) regardless of the ratio of the initial components.

Major approaches to the synthesis of phosphazene-containing epoxide oligomers via the reactions of the functional derivatives of cyclophosphazenes with glycidol or epichlorohydrin as well as oxidation of double bonds in the organyl fragments linked to the phosphorus atoms have been considered. The main regulations of the mentioned processes have been compared and the possibilities to adjust the properties of the phosphazene-containing epoxide oligomers, which form fire-resistant or completely non-inflammable compositions upon curing with the agents commonly used with epoxy resins, have been shown.

Methacrylate-containing phosphazene oligomers are synthesized by the reaction of phosphazene-containing epoxy compounds with methacrylic acid and characterized by 1 Н and 31 Р NMR spectroscopy, MALDI-TOF mass spectrometry, and functional analysis. Methacrylate-containing phosphazene oligomers with the addition of 0.5% hydroquinone are stable under storage at normal temperature for 2 to 3 weeks but are easily involved in benzoyl peroxide-initiated copolymerization with methyl acrylate to give rise to copolymers with the quantitative content of the gel fraction.

The reaction of epoxyphosphazenes with methacrylic acid was used to synthesize methacrylate-containing phosphazene oligomers (MPO) used to modify dental restorative materials.The introduction of 1015 wt.% MPO into the base bis-methacrylate binder composition can significantly increase the adhesion of modified cured compositions to tooth tissues and metals, as well as improve water resistance while maintaining the required strength indicators and other physicochemical characteristics required by GOST.

Phosphazene-containing epoxy oligomers (PEOs) were synthesized by the one-pot method by means of the interaction of hexachlorocyclotriphosphazene, diphenylolpropane, and epichlorohydrin at 80°C in the presence of solid KOH. In contrast to similar PEOs previously obtained at a lower temperature, according to MALDI–TOF spectrometry, the phosphazenes synthesized in this work contain about 10% of compounds with two or three phosphazene rings linked by one or two oxyaryleneoxy radicals, while the total number of epoxide groups in the molecules of these compounds is from four to eight. PEOs are cured with polyamine hardeners to form compositions with increased fire resistance, while retaining the basic properties of conventional epoxy materials.

The influence of the phase state of the reaction system and the HCl concentration during hydrolytic polycondensation of methyltrichlorosilane on the composition of the formed oligomers, their stability during storage and ability to thermal curing is shown. The technological production process is developed and the scheme of a pilot plant for obtaining oligomethylsilsesquioxanes used for the production of highly filled thermo- and fire-resistant polymer composite materials is presented.

Oligomeric hydroxyaryloxycyclotriphosphazenes P3N3Cln(OC6H5)x(OC6H4OH)y are obtained by the polycondensation of phenoxychlorocyclotriphosphazenes with the general formula P3N3Cl(6 − x)(OC6H5)x (x = 3.1, 4.5) with an excess of resorcinol under homogeneous (pyridine) and heterogeneous (K2CO3) acceptance of HCl in a yield of 60–85%. Full substitution of the chlorine atoms in the specified oligomers (n = 0) under homogenous acceptance of HCl by pyridine is reached only at a molar ratio of phenoxychlorocyclophosphazene : resorcinol = 1 : 12; the formed oligomers contain up to 3% Cl at a ratio of 1 : 6. The structure of the compounds present in the composition of oligohydroxyaryloxycyclotriphosphazenes and their relative concentration are determined by 31P NMR spectroscopy and MALDI-TOF mass spectrometry.

By the reaction of hexachlorocyclosphosphazene with resorcinol in the immiscible pyridine–cyclohexane system, hexa-(m-hydroxyphenoxy)cyclotriphosphazene is synthesized, the optimum yield of which of 84% is achieved in a uniform mixture of the indicated solvents and the molar ratio HCP : resorcinol = 1 : 12. When used for the synthesis of oligomers mixtures of chlorocyclophosphazenes (PNCl2)n, where n = 3, 4, and 6, also complete replacement of chlorine atoms occurs, and with a yield of up to 80%, the formation of mixed oligohydroxyphenoxycyclophosphazenes takes place. The synthesized oligomers are characterized using 31P NMR spectroscopy and MALDI-TOF mass spectrometry.

The main features of two methods for the synthesis of phosphazene-containing epoxy oligomers— namely, the methods based on oxidation of double bonds in organooxyphosphazenes and on the reaction of chlorocyclophosphazenes with diphenols and the subsequent interaction of the resulting hydroxy-aryloxy phosphazenes with epichlorohydrin—were examined. Using the example of hexa- and octa-eugenol derivatives of the corresponding cyclophosphazenes, optimal conditions were established for the oxidation of allyl groups of these compounds with peroxy acids and hexa- and octa-epoxide cyclophosphazenes were characterized. It was noted that the epoxidation of eugenol derivatives of a mixture of cyclophosphazenes with three to eight phosphazo groups is accompanied by side reactions leading to the formation of P–OH bonds and the partial opening of oxirane cycles. Bisphenol A phosphazene-containing oligoepoxides were synthesized both via the stage involving the formation of hydroxy-aryloxy cyclophosphazenes and their subsequent epoxidation with epichlorohydrin and via the direct interaction of chlorocyclophosphazenes with an excess of bisphenol A (BPA) in the presence of solid alkali. In the latter case, the resulting oligomers are mixtures of the conventional epoxide and phosphazene-containing epoxy oligomers. The content of the latter can be adjusted up to 50%. The synthesized oligomers contain 1–5% phosphorus. They can be cured by conventional hardeners to form flameproof or noncombustible compositions.

The results of investigating the rheological properties and processing characteristics of a system consisting of 60 wt% epoxy bisphenol A resin of type ED-20 and 40 wt% phosphazene-containing epoxy oligomer are given. The kinetic dependences of the shrinkage, residual stresses, and rheokinetics are obtained, and the gelation times, activation energy of viscous flow, and glass transition temperature are determined.

Phosphazene-containing epoxy oligomers are obtained through a one-stage method via the interaction of hexachlorocyclotriphosphazene with an excess of diphenylolpropane in the medium of epichlorohydrin in the presence of a solid alkali. With the use of 31 Р NMR and MALDI mass spectrometry, it is shown that the main components of the phosphazene fraction are penta- and tetra-aryloxysubstituted cyclotriphosphazene compounds with the corresponding numbers of epoxy groups. The maximum content of the phosphazene fraction in phosphazene-containing epoxy oligomers (~40 wt %) is attained at a hexachlorocyclotriphosphazene-to-diphenylolpropane molar ratio of 1: 8. Phosphazene-containing epoxy oligomers cured with isomethyltetrahydrophthalic anhydride have oxygen indexes of 26–28 and are self-extinguishing.

The rheological and rheokinetic properties of a two-component binder consisting of epoxy-diane oligomers and the oligoepoxyphosphazenes PEO-1 (30 wt %) and PEO-2 (40 wt %) are studied. The viscosities of the initial oligomers at 40°C are 130 (PEO-1) and 270 (PEO-2) Pa s; the activation energies of viscous flow in the range 40–70°C are from 122 to 128 kJ/mol. The addition of equivalent amounts of curing agents, such as triethylenetetramine or iso -methyltetrahydrophthalic anhydride, reduces the initial viscosity of a composition, most strongly in the presence of the second curing agent (by a factor of 50–100). The activation energies of the cure process with triethylenetetramine in the range 45–95°C are 89 (PEO-1) and 125 (PEO-2) kJ/mol, and the gelation time at 55°C is 6 min for both oligomers. The time of gelation for the system PEO– iso -methyltetrahydrophthalic anhydride at 90°C is 475 min, and the glass-transition temperatures of the cured compositions are 238 (PEO-1) and 250°C (PEO-2), as evidenced by thermomechanical studies.

The effect of epoxy phosphazene on the curing parameters of an epoxy amine composition containing epoxy phosphazene was studied via rotational viscometry. The presence of epoxy phosphazene accelerates the process and changes the pattern of polymer-network formation. As a result, the dynamics of the increase in viscosity changes.

With the use of MALDI mass spectrometry and 29 Si NMR spectroscopy, the molecular-mass compositions of oligomers prepared via partial acidolysis of PhSi(OMe) 3 by acetic acid have been studied. Depending on the molar ratio of m PhSi(OMe) 3 and n CH 3 COOH ( m / n ), a wide variety of oligophenyl-methoxysiloxanes with average compositions of [(PhSiO 1.5 ) m (OMe 0.5 ) (3 − 2 n )/ m ] p are formed. Through analysis of the molecular masses (MALDI, GPC) and 29 Si NMR spectra of the products, the types of molecular structures have been determined. After 66.67–86.67% completion of the process, the change from linear, branched, cyclic, and polycyclic structures to fully condensed polyhedral structures is observed.

The molecular-mass compositions of the products of partial acidohydrolytic polycondensation that are formed during the interaction of MeSi(OMe)3 with CH3COOH have been studied via MALDI mass spectrometry. It has been shown that, depending on the molar ratio of MeSi(OMe)3 and CH3COOH (m/n), a wide range of oligomethylmethoxysiloxanes with the average composition [MeSiO n/m (OMe)(3 − 2n/m)] p are formed. The analysis of molecular masses and 29Si NMR spectra of the products has revealed various types of molecular structures, which change from linear, branched, and cyclic to polycyclic clusters with condensed cycles after a change in the degree of polycondensation α = 100 × [2n/3m] from 66.67 to 83.33%. At a degree of polycondensation of α = 86.67% or higher, the polycyclic clusters form a spatially crosslinked structure (gel).

A single-stage synthesis of phosphazene-containing epoxy oligomers via the direct interaction of hexachlorocyclotriphosphazene, diphenylolpropane and epichlorohydrin has been proposed. The resulting products are composed of a common epoxy-diane oligomer and an epoxyphosphazene component, with the content of the latter being up to 45 wt %. Oligomers with epoxy numbers up to 22 were characterized with the use of gel permeation chromatography, chromatography-mass spectrometry, laser mass spectrometry, 31 P NMR spectroscopy, and 1 H NMR spectroscopy.

The synthesis of eugenol derivatives of octachlorocyclotetraphosphazene and mixtures of oligomer chlorocyclophosphazenes [NPCl2]3–8 was performed. Not yet described octakis(4-allyl-2-methoxyphenoxy)cyclotetraphosphazene was isolated in the crystalline form and identified via 31P and 1H NMR spectroscopy, laser mass spectrometry, DSC, and TGA. Oligomers with epoxy numbers of 15–16% and molecular masses from 1400 to 1800 were prepared via epoxidation of the synthesized eugenol derivatives with m-chloroperbenzoic acid. Some assumptions on the nature of side reactions occurring in the course of epoxidation were made.

With the use of 31 P NMR spectroscopy and gas chromatography-mass spectrometry, the partial ammonolysis of PCl 5 by ammonium chloride in chlorobenzene in the presence of zinc chloride is investigated. The use of zinc chloride reduces the reaction time to 1.5 h and increases the yield of oligomeric chlorophosphazenes up to 95%. Some assumptions are made about the role of ZnCl 2 in the process and about the feasibility of the mechanism of formation of higher cyclic chlorophosphazenes, the hexamer and the octamer.