A series of benzoxazine monomers were synthesized based on 3,3 '-, 3,4 '-, and 4,4 '-diaminodiphenylmethane and salicylic aldehyde (P-3,3 '-d, P-3,4 '-d, and P-4,4 '-d, respectively) in order to identify the influence of the position of the amino group in an aromatic amine on the ability of the monomer to polymerize, on its behavior during the polymerization process, and on the structure and properties of the polymers [poly(P-3,3 '-d), poly(P-3,4 '-d), and poly(P-4,4 '-d), respectively] formed during their curing. The chemical structure of all obtained benzoxazines was characterized using H-1 and C-13 NMR spectroscopy. Differential scanning calorimetry was used to study the curing process of benzoxazines as well as to determine the glass transition temperature of polymers based on them. The thermal stability of each polymer was studied by using thermogravimetric analysis. It was found that P-3,3 '-d has the lowest melting point and the highest glass transition temperature for poly(P-3,3 '-d), and the position of the amino group in the initial diamine does not affect the onset of the polymerization process in the studied benzoxazines. The resulting compounds can be used as components of resins for polymer matrix composites with improved properties.

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.

Modern research in the field of synthesis of organofunctional oligosilsesquioxanes is considered. Relationships between the composition and structure of oligomeric organosilsesquioxanes and the conditions for their formation during the hydrolytic and acidohydrolytic polycondensation of organotrialkoxysilanes containing various functionalities, such as methacrylic, aminopropyl, carboxyl, and cyclotriphosphazene groups, in organic radicals bonded to silicon atoms are shown. A comparative analysis of approaches to the synthesis of organofunctional incompletely condensed oligosilsesquioxanes has been carried out.

Polybenzoxazine based on 3-phenyl-2,4-dihydro-1,3-benzoxazine is studied by X-ray photoelectron spectroscopy. It is shown that during polymerization, along with oxazine ring opening, formation of methylol and other functional groups involved in three-dimensional structure development occurs.

Методом рентгенофотоэлектронной спектроскопии исследован полибензоксазин на основе 3-фенил-2,4-дигидро-1,3-бензоксазина. Установлено, что при полимеризации кроме раскрытия оксазинового цикла происходит образование метилольных и других функциональных групп, участвующих в формировании трехмерной структуры.

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.

Organophosphazenes are of interest due to the combination of increased mechanical and thermal properties of polymer materials obtained with their use, however, they are characterized by a complex multi-stage synthesis. Moreover, the high viscosity of phosphazene-containing epoxy resins (PhER) makes their processing difficult. To simplify the synthesis of PhER, a one-step method was developed, and bisphenol F was chosen, which also provided a decrease in viscosity. In the current study, PhER were formed by a one-stage interaction of hexachlorocyclotriphosphazene (HCP) with bisphenol F isomers and epichlorohydrin in the presence of alkali, which was a mixture of epoxycyclophosphazenes (ECPh) with a functionality from 1 to 4 according to the results of MALDI-TOF analysis. Conventional epoxy resins based on bisphenol F, also formed during the process, showed high mechanical properties and glass transition temperature, and the reactivity of the obtained resins is similar to the base epoxy resins based on bisphenols A and F. Cured PhER had higher or the same mechanical properties compared to base epoxy resins based on bisphenol A and F, and a glass transition temperature comparable to base epoxy resins based on bisphenol F: glass transition temperature (Tg) up to 174.5 °C, tensile strength up to 74.5 MPa, tensile modulus up to 2050 MPa, tensile elongation at break up to 6.22%, flexural strength up to 146.6 MPa, flexural modulus up to 3630 MPa, flexural elongation at break up to 9.15%, and Izod impact strength up to 4.01 kJ/m2. Analysis of the composition of the obtained PhER was carried out by 1H and 31P NMR spectroscopy, MALDI-TOF mass spectrometry, X-ray fluorescence elemental analysis, and contained up to 3.9% phosphorus and from 1.3% to 4.2% chlorine. The temperature profile of the viscosity of the resulting epoxy resins was determined, and the viscosity at 25 °C ranged from 20,000 to 450,000 Pa·s, depending on the ratio of reagents. The resins studied in this work can be cured with conventional curing agents and, with a low content of the phosphazene fraction, can act as modifiers for traditional epoxy resins, being compatible with them, to increase impact strength and elasticity while maintaining the rest of the main mechanical and processing properties, and can be used as a resin component for composite materials, adhesives, and paints.

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.

As a result of this research, it was established that the chlorine atom replacement rates in hexa-chlorocyclotriphosphazene by o-, m-, and p-methylanilines’ temperatures are crucial in determining which reaction is made. The speed of reaction practically does not affect the polarity of the synthesis solvent. For the formation of fully substituted o-, m-, and p-arilaminocyclotriphosphazenes, the reaction takes 5 h and is carried out in the diglyme at its boiling temperature. The structure of the synthesized AAP was confirmed by 31P and 1H NMR spectroscopy and MALDI-TOF mass spectrometry. By means of synchronous DSK and TGA, it is found that the synthesized AAP are crystalline and their thermal destruction has a stepped character. Thermal destruction is shown to be accompanied by the simultaneous removal of three aniline molecules from the AAP molecules. Conducted curing of epoxy resin DER-331 is carried out using the AAP as a curing agent. It has been established that due to steric difficulties, o- AAP does not interact with epoxy resin, unlike m- and p- AAP. The gel fraction in curing resin is measured, and the AAP relate to the stage processes of macromolecule formation. The result is that polymers based on DER-331 and m-, p-AAP have a gel fraction content up to 97 mass. %. These polymers have glass-transition temperatures 80 and 85 °C (m- and p-AAP-based, respectively) and demonstrate fire resistance to standard UL-94 of category V-0.

Phosphazene-containing benzoxazine compounds based on diamines of various structures were obtained as a result of the work performed. The resulting compounds were characterized by 1H NMR spectroscopy, the thermal and rheological properties of benzoxazines based on diamines were studied, and data of flammability were presented. The effect of the structure of the initial diamine on the properties of the resulting monomer and polymer has been studied. The curing kinetics of compositions of benzoxazines with different contents of phosphorus-containing flame retardant catalysts based on hexachlorocyclotriphosphazene and m-toluidine was studied. The synthesized monomers and the resulting compositions of benzoxazines with flame retardant catalysts can be used as heat and fire resistant binders for polymer composite materials, as well as hardeners for epoxy resins.

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.

Abstract In this study, the application of methyl methacrylate (MMA) resin as the binder and standard sand as the aggregate has been employed to prepare the repair materials that can be cured in the sub-zero temperature environment. For this purpose, the redox initiation system of benzoyl peroxide (BPO) and N,N-dimethyl-p-toluidine (DMPT) has been used. Subsequently, the influence of initiator and accelerator content on the compressive strength, flexural strength, curing time and other properties of the materials has been revealed. At an ambient temperature of 0 °C, with BPO = 4.5% and DMPT = 3.5%, the developed repair materials can be cured within 31 min, and the 1 h compressive strength reaches 84.6 MPa. At an ambient temperature of −25 °C, with BPO = 4% and DMPT = 5%, the repair materials can be cured within 43 min, with the 1 h compressive strength reaching 53.4 MPa. The materials can be swiftly cured at low-temperature and exhibit excellent mechanical properties, thus, confirming their suitability for extreme environments. Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and other techniques have been employed to characterize the developed materials.

This study reports on a series of crosslinked poly(arylene ether)s with POSS in the main chain. The fluorinated and terminated poly(arylene ether)s were first synthesized by the nucleophilic reaction of diphenol POSS and decafluorodiphenyl monomers, including decafluorobiphenyl, decaflurobenzophenone, and decafluorodiphenyl sulfone. They were then reacted with 3-hydroxyphenyl acetylene to produce phenylacetylene-terminated poly(arylene ether)s. The polymers were of excellent processability. When heated to a high temperature, the polymers converted into a crosslinked network, exhibiting a low range of dielectric constant from 2.17 to 2.58 at 1 HMz, strong resistance against chemical solutions, low dielectric losses, and good thermal and hydrophobic properties.

Phosphazenes are a well-studied class of organometallic compounds with perspective characteristics, already tested in various applications. However, until now, three-dimensionally crosslinked structures based on them are primarily obtained by irradiation (that is UV and Cobalt-60). It is generally accepted that such processes proceed via the mechanism of the cleavage of C-H bonds present in the organic substituents, which clearly indicates the lack of selectivity and the impossibility to control the crosslinking degree and distribution. Within this article, multifunctional organosubstituted structures based on the short-chain penta-functional trichlorophosphazodichlorophosphonyl with eugenol and methacrylic fragments were obtained. All products were characterized by1H and31P NMR spectroscopy and MALDI-TOF mass spectrometry. The tendency of compounds with linear methacrylic substituents to undergo the phosphazene-phosphazane rearrangement, so that the dominant reaction product turns to the tetrasubstituted derivative, has been shown. All the obtained compounds can be used as the independent monomers to obtain rigid hybrid organo-inorganic matrices, as well as polyfunctional crosslinking agents for various polymers.

Finding new ways for the preparation of cross-linked structures is a significant problem in terms of materials for biomedical application, lithium batteries electrolytes, and etc. Within this work we have studied the possibility to utilize hydrosilylation and Piers-Rubinsztajn reactions to obtain cross-linked model phosphazene compounds, containing eugenoxy and guaiacoxy groups. It was shown that Piers-Rubinsztajn reaction cannot be efficiently used to prepare tailored polymer-matrix, due to the catalyst deactivation by nitrogen atoms of phosphazene units. A number of cross-linked phosphazene-based materials was obtained with the use of hydrosilylation reaction and their properties were studied by NMR spectroscopy, FTIR, DSC, and TGA. This work showed a perspective for the use of eugenoxy functional groups for the preparation of three-dimensional hybrid phosphazene/siloxane-based materials for various applications.

Despite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a given size and for the controlled cyclization reaction when it is secondary and undesirable. We synthesized a series of short linear phosphazene oligomers with the general formula Cl[PCl2=N]n–PCl3+PCl6– and studied their tendency to form cyclic structures under the influence of elevated temperatures or in the presence of nitrogen-containing agents, such as hexamethyldisilazane (HMDS) or ammonium chloride. It was established that linear oligophosphazenes are inert when heated in the absence of the mentioned cyclization agents, and the formation of cyclic products occurs only when these agents are involved in the process. The ability to obtain the desired size phosphazene cycle from corresponding linear chains is shown for the first time. Known obstacles, such as side interaction with the PCl6– counterion and a tendency of longer chains to undergo crosslinking elongation instead of cyclization are still relevant, and ways to overcome them are being discussed.