Properties of composite materials based on epoxy resin modified with dibutyltin dibromide

The paper reports the data on the synthesis of a new, previously not described, series of oligodiuretancarbofunctional alcohols based on aliphatic individual or oligomeric diols and polyisocyanate at the following ratio: one gram-equivalent of polyisocyanate per one mole of the corresponding diol. The isolated compounds are transparent, homogeneous, slightly colored dark-colored substances, some of which crystallize under room conditions, and the other part is a very viscous and sticky liquid. Their physicochemical constants are given (nD20, wt.% of –OH groups, wt.% of the latter –NCO groups, and urethane group content). Such oligodiuretan-containing carbofunctional alcohols are well soluble in ketones, esters, ethers, chlorine-containing and aromatic hydrocarbons, and aprotic solvents. They are poorly and even insoluble in non-polar hydrocarbons (hexane, heptane, etc.). Their structure is confirmed by functional analysis and IR spectra.

Synthesis and properties of oligodiurethane-containing carbofunctional alcohols based on polyisocyanate

Kuzmenko¹,

KUZMENKO²,

Filinska³

et al. 2022

Synthesis and properties of oligodiuretane diisocyanates and oligotetraurethanes based on a mixture (2.4÷2.6) of toluene diisocyanate

Kuzmenko¹,

SPORYAGIN²,

KUZMENKO³

et al. 2023

By the reaction of a mixture of isomers (2.4-2.6) of toluene diisocyanate with aliphatic, individual or oligomeric diols (such as polyoxypropylene glycols of different molecular weight) in cyclohexanone, oligodiurethane diisocyanates with the diol component of different nature and length in their structure are synthesized in the first stage. In the second stage, the synthesized oligodiurethane diisocyanates were blocked by monofunctional aliphatic alcohols of normal structure with different lengths of fatty radical. The structure of the latter is confirmed by the absence of absorption bands characteristic of free –NCO groups in the IR spectra. Both series of isolated oligodiureta diisocyanates and oligotetraurethanes are characterized by refractive index and Ubellode drop temperature, molecular weights, content of free –NCO groups, and IR spectra. They are well soluble in esters, ethers, chlorinated and aromatic hydrocarbons, ketones, and aprotic solvents; they are poorly soluble in aliphatic hydrocarbons. The presence in the structure of such compounds of polar urethane groups simultaneously with relatively high molecular weight suggests that they will be useful not only as plasticizers, but also as modifiers of the properties of polymers and composite materials.

Using the method of calculating the total molar energy of cohesion to choose the most effective plasticizer

Kuzmenko,

Sporyagin,

Kuzmenko

et al. 2023

It is known that products made of polar, crystallized, and high-strength polymers (polyamides, polyesters, cellulose triacetate, polyvinyl chloride, etc.) lose their initial properties that reduce reliability and durability in the process of operation and even during long-term storage due to the increase in internal stresses in them caused by crystallization processes over time. To reduce the impact of such processes on the properties of polymer products, special substances are introduced into their composition, plasticizers, the selection of which is usually carried out empirically, which is not always successful. We proposed in this study to use the ratio of the calculated total molar volumetric energy of cohesion of the compound (the cumulative interaction of interatomic and intermolecular forces in the composition of the compound) to its molecular weight as the specific mass total energy of cohesion, which can be compared with a similar indicator for a plasticizing polymer. The use of such an approach makes it possible to purposefully, even before experimental verification, evaluate the suitability of using this or that compound, oligomer, or polymer as a plasticizer (or modifier), or develop a molecular structure of a new, necessary compound with the inclusion of certain groups in its composition for the purpose of further use as a plasticizer or modifier. In addition, there is an opportunity to monitor the influence of individual structural components of a new compound, oligomer or polymer, its molecular weight, side substituents and their nature on the value of the specific mass total energy of cohesion, as well as to reduce the time for performing research works in this direction and expenses for their implementation.