E. M. Chistyakov

Synthesis and modification of oligo(aryloxycyclotriphosphazenes) based on 4,4′-dihydroxydiphenyl-2,2-propane

Oligo(aryloxyphosphazenes) are synthesized on the basis of diphenylolpropane and hexachlorocyclotriphosphazene via the phenolate method. Corresponding functional derivatives are obtained through treatment of the oligomers with methacryloyl chloride, glycidyl methacrylate, and epichlorohydrin. GPC data indicate that modification is accompanied by an increase in the molecular mass of the oligomers. Epoxidation of a specially synthesized hexaallyloxy derivative of oligo(aryloxycyclotriphosphazene) with m-chloroperbenzoic acid proceeds incompletely to yield an oligomer with a content of epoxy groups below 6%. All of the compounds are characterized with the use of 31P and 1H NMR spectroscopy.

Halogenated hydroxy-aryloxy phosphazenes and epoxy oligomers based on them

By partial substitution of the chlorine atoms in hexachlorocyclotriphosphazene for halophenols and subsequent reaction of the resulting halogenated phenoxy phosphazene and 2,2-di(4-hydroxyphenyl)propane monophenolate hydtoxy-aryloxy phosphazenes were synthesized with a molecular weight of 1100–1400 g mol−1. Epoxide oligomers (epoxy number of 6–8%), which are cured with the formation of non-combustible compositions [PV-0 class of resistance to combustion according to State Standard (GOST 28157-89)], were obtained by reaction of these compounds with epichlorohydrin. Introduction of 5–50 wt% halogenated epoxyphophazene oligomers in industrial resin ED-20 can significantly improve the flame resistance of compositions based on these compounds.

Polymeric dental composites modified with carboxy phosphazene methacrylates

Oligophosphazenes containing carboxy and polymerizable methacrylate groups were prepared by the reaction of hexa-p-carboxyphenoxycyclotriphosphazene with glycidyl methacrylate. Introduction of these oligomers in an amount of up to 10 wt % into methacrylate filling dental composites enhances their adhesion to tooth tissues and metals by a factor of 5–7 and the compression strength by 20–30%.

Methacrylate composites containing maleic derivatives of cyclotriphosphazene

Oligophosphazenes containing carboxyl groups and copolymerizable double bonds are synthesized through the interaction between hexa-p-hydroxymethylphenoxycyclotriphosphazene and maleic anhydride. The synthesized compounds with a controlled ratio of carboxyl groups and double bonds are used as modifiers of methacrylate dental composites that exhibit high adhesion to hard dental tissues and metals.

Thermal polycondensation of hexa-p-hydroxymethylphenoxycyclotriphosphazene

A procedure for the synthesis of hexa-p-hydroxymethylphenoxycyclotriphosphazene is optimized. The thermal characteristics of this compound are studied, and its capability for thermal self-con-densation is demonstrated. The main steps of polycondensation of hexa-p-hydroxymethylphenoxycyclotriphosphazene involve the formation of methylene ether bonds accompanied by the evolution of water and their further scission without formation of formaldehyde. The resulting polymer is thermally stable up to 470°C.

Carboxyl derivatives of phosphazenes

The review describes the modern methods of synthesis and chemical modification of carboxylcontaining phosphazenes. The possibility of their use in the synthesis of polyamides, epoxy resins, star-shaped and structured polymers, hydrogels, and metal complexes is considered. Carboxyl-containing phosphazenes and their derivatives are of great interest for medicine, electronics, photonics, and design of multipurpose hightech composite materials, offering wide opportunities for further research and application.

Synthesis of oligomeric epoxycyclotriphosphazenes and their properties as reactive flame-retardants for epoxy resins

GRAPHICAL ABSTRACT ABSTRACT Hydroxyaryloxycyclophosphazenes containing 2–4 OH groups have been synthesized by the substitution of chlorine atoms of hexachlorocyclotriphosphazene via the reaction with sodium phenolates of halogenophenols followed by the interaction with sodium monophenolate of diphenylolpropane. Oligoepoxyphosphazenes (OEPs) with molecular masses up to 2000 and the contents of epoxy groups, phosphorus, and halogens atoms about 5–8, 5–8, and 5–11%, respectively, have been obtained via the interaction of the aforementioned phosphazenes with epichlorohydrin. The curing of the OEPs with amines or acid anhydrides gives rise to the formation of self-extinguishing composites. The incorporation of the OEPs (5–75 wt %) into commercial epoxy resins followed by their curing, results in the formation of composites with excellent nonflammability or capability of self-quenching, and good dielectric, heat resistant and mechanical properties. It has been established that mixtures of common epoxides with different amounts of the OEPs can be synthesized by a “single-reactor” method.

Synthesis and structure of hexa-p-acetamidophenoxycyclotriphosphazene

Hexa-p-acetamidophenoxycyclotriphosphazene was synthesized and examined by the 31P and 1H NMR spectroscopy and XRD analysis.