V. A. Pankratov

Reaction of cyanurates with the epoxide ring

ConclusionsIn the case of the reaction of triphenylcyanurate and phenyl glycidyl ether, we showed that the oxirane rings may react at high temperature with the cyanurate rings to form isocyanurate fragments, which, in turn, react with excess epoxide to form oxazolidone rings.

Thermal and thermal-oxidative degradation of polycyanates☆

Abstract The thermal and thermal-oxidative degradaation of polycyanates based on 4,4′-dicyanatodiphenyl (PC-4) and 9,9-bis-(4-cyanatophenyl)fluorene (PC-9) have been investigated over a wide range of temperatures. The kinetics of decomposition of the polycyanates have been studied and the apparent energies of activation for the over-all process of breakdown of the polymers and for the formation of carbon dioxide in degradation in vacuo have been determined. It was found that moisture present in the polymers has a substantial effect on the nature and extent of decomposition. It is suggested that degradation of the polycyanates begins with hydrolytic scission of the ester bond and that this is followed by breakdown of the triazine ring by both heterolytic and homolytic mechanisms.

The properties of polyisocyanurates produced by the polycyclotrimerization of aromatic with aliphatic diisocyanates

Abstract The thermal stability, heat resistance and the physico-mechanical properties have been studied on homo- and copolymers produced by a polycyclotrimerization (PCTM) of various aromatic with aliphatic diisocyanates (DIC). The effect of the DIC type and also of the ratio of aromatic to aliphatic components have been examined. The polyisocyanurates (PICU) produced by a selective PCTM have been found to possess improved physico-mechanical properties and thermal stabilities due mostly to the polar interactions of the C = O groups situated at the joints of the polymeric network.

Polycyclotrimerization of aryldicyanates in the presence of Cr3+ acetylacetonate☆

Abstract A kinetic scheme for the polycyclotrimerization of an aryldicyanate has been proposed on the basis of the kinetic features governing the polycyclotrimerization of 2,2-bis-(4-cyanotophenyl) propane in the presence of (AcAc) 3 Cr as catalyst: this scheme has been analysed and compared with the experimentally established facts and with results that follow from the scheme. It has been shown that all the kinetic features may be quite satisfactorily described by the scheme proposed.

Effect of the nature of solvent on the polycyclotrimerization rate of 2,2-bis-(4-Cyanatophenyl) propane☆

The solvent nature was found to have a marked effect on the reaction rate and the thermal effect in the polycyclotrimerization of 2,2-bis-(4-cyanatophenyl) propane in the presence of chromium acetylacetonate. Placing the solvents in order according to the polycyclotrimerization rate we have: ditolylmethane > nitrobenzene > anisole > diglyme. The thermal effect for the polycyclotrimerization in nitrobenzene anisole and diglyme is 5–10 kcal/mole lower than in ditolymethane.

Rheological properties of the gels obtained by solution polycyclotrimerization of diisocyanates

Abstract The elastic properties and swelling of gels obtained by plycyclotrimetrization of diisocyanates in various solvents have been investigated, along with those of dry networks obtained from the gels after elimination of solvents, in relation to the conditions of their synthesis governing the mechanism of network formation. For the dry networks it was found that the degree of swelling increases and the elastic modulus is reduced when the initial gel concentration decreases. Anomalous elastic properties of the gels, and irreversibility of network swelling before and after elimination of the solvent are accounted for by the role of solution macrocyclization leading to a more complex network topology compared with the polycyclotrimerization in bulk.

Effect of the structure of polycyanates prepared by polycyclotrimerization of aryl dicyanates on their thermal stability

A comparative study has been made of the thermal and thermal-oxidative degradation under rising temperature and isothermal conditions of polycyanates, which are densely crosslinked polymers, prepared by polycyclotrimerization of a number of aryl dicyanates, differing mainly in the substituents on the central carbon atom. It is shown that all the polycyanates studied begin to decompose within a fairly narrow range of temperatures (385–405°) and the nature of the decomposition is the same in most of the polymers.

Investigation of the reaction of thionyl chloride with dimethylformamide

1. The interaction of dimethylformamide with thionyl chloride was investigated at various temperatures. 2. At the beginning of the interaction of dimethylformamide with thionyl chloride, an unstable addition product of thionyl chloride at the carbonyl oxygen of dimethylformamide is formed

The polycyclotrimerization of isocyanates

\begin{gathered} \hfill \\ [(CH_3 )_2 \mathop N\limits^ \oplus = C\begin{array}{*{20}c} / \\ \backslash \\ \end{array} \begin{array}{*{20}c} {O - SO - Cl} \\ H \\ \end{array} ]Cl^ \ominus \hfill \\ \end{gathered}