Сrosslinked polymer memranes are obtained by the heat treatment of films prepared from a solution of a mixture of bromine-containing poly(1-trimethylsilyl-1-propyne) (PTMSP) and polyfunctional amine polyethyleneimine (PEI) as a crosslinking agent. Crosslinked products are identified from IR spectra, elemental analysis data, and stability of reaction products to a solvent (CCl4), in which the original brominated PTMSP is soluble. According to the IR spectra, the crosslinking reaction occurs via reactive C–Br bond in bromine-containing PTMSP with the participation of PEI amino groups at a temperature above 90°С. The crosslinking of bromine-containing PTMSP makes it resistant to organic solvents. An increase in the content of PEI in the mixture correlates with the proportion of bromine atoms involved in the reaction. For brominated PTMSP films crosslinked by PEI transport parameters for individual gases and in the mixture n-butane/methane (98.4 mol P_n-C_4H_10 = 12 000 Barrer) and selectivity for n-butane separation from a mixture with methane ( α_n-C_4H_10/CH_4 = 13).

The polymerization of 1-trimethylsilyl-1-propyne mediated by catalytic systems based on Nb and Ta pentafluorides is carried out. Using solid-state 13С NMR spectroscopy, it is shown that the catalysts based on group V metal fluorides possess a well-defined trans-stereoregulating ability and produce trans-enriched polymers compared with analogous samples synthesized using Nb and Ta chlorides and bromides since they have a smaller ligand at the active center of the growing chain. A high trans-stereoregularity of poly(1-trimethylsilyl-1-propyne) is responsible for its insolubility in organic solvents. As evidenced by low-temperature argon sorption, all the synthesized polymers have high BET specific surface area (above 600 m2/g) and micropore volume (above 0.30–0.45 cm3/g). In combination with resistance against organic compounds, this makes them attractive materials for use as fillers of composite membranes and sorbents for the sorption of gases and vapors of organic compounds from streams of commercial mixtures of various composition.

The article describes a new method for the preparation of cross-linked poly(1-trimethylsilyl-1-propyne) (PTMSP) using aliphatic diamines. The developed two-stage method includes selective functionalization of the polymer by the bromination reaction of PTMSP and the subsequent use of functional groups in the polymer for cross-linking by the reaction of bromine substitution in the polymer with a diamine. Under the conditions of a polymer solution with added diamines, the effect of the chain length of the diamine, the reaction temperature, and the bromine content in the polymer on the cross-linking efficiency was studied. It was shown that the cross-linking efficiency depends on the length of the diamine chain and on the bromine content in PTMSP. The identification of cross-linked products was carried out on the basis of elemental analysis data, the stability of the reaction product to the solvent (CCl4), in which the starting brominated PTMSP dissolves, and by IR spectroscopy. Cross-linked films of brominated PTMSP resistant to organic solvents were obtained using 1,12-diaminododecane, which showed the highest efficiency in the reaction in solution. The individual gases (H2, N2, O2, CH4, CO2, and n-C4H10) and mixed n-butane/methane permeability of the pure, brominated and cross-linked PTMSP films were measured. The obtained data demonstrated that cross-linking reduces pure gases permeability as well as mixed n-butane and methane permeability of cross-linked PTMSP films in comparison with initial PTMSP. Cross-linked PTMSP film showed that ideal selectivity calculated from pure gas measurements enhanced (for example, ideal selectivity for СO2/N2 increased from 6.2 to 10.1) or stayed nearly constant (ideal selectivity for n-С4H10/CH4 was 3.6–3.9) compared to initial PTMSP. Whereas, in contrast, the mixed n-butane/methane selectivity decreased from 22 (unmodified PTMSP) to 14 (cross-linked PTMSP). The nanoporous structure unmodified, brominated and cross-linked PTMSP films was studied by the method of low-temperature nitrogen sorption. The decrease in gas/vapor permeability correlates with changes in the specific surface area and pore volume in the series: PTMSP - brominated PTMSP – cross-linked PTMSP. The high values of the specific surface area and volume of micropores indicate a highly developed nanoporous structure of the obtained cross-linked polymer, which is promising as a membrane and highly sorbing material.

This paper presents the results of a study of the effect of thermally activated relaxation on the gas permeability of films prepared from poly(1-trimethylsilyl-1-propyne) (PTMSP) of different configurational composition (the content of cis-units varies from 40 to 80%). Films of both pure PTMSP and those prepared with the addition of the antioxidant Irganox 1076 have been subjected to heat treatment. When polymer films have been heated without a stabilizer, the cis-enriched sample of PTMSP (80% cis-units) showed the highest stability. The addition of an antioxidant significantly increases the resistance of PTMSP films to thermal effects, while the trans-enriched sample (40% of cis-units) has shown the highest resistance. It has been found that in the first 40 h of heating, the trans-enriched PTMSP shows a faster relaxation compared to the cis-enriched samples, and upon further heat treatment, the decrease in the permeability coefficients occurs more slowly and at approximately the same rate for all samples. It is shown that the thermally activated relaxation of PTMSP films leads to an increase in the ideal selectivity, which is especially noticeable for the CO2/N2 pair ($${{\alpha }_{{{\text{C}}{{{\text{O}}}_{{\text{2}}}}{\text{/}}{{{\text{N}}}_{{\text{2}}}}}}}$$ reaches 8.2 for PTMSP samples containing 40 and 80% cis-units). X-ray diffraction data indicate a decrease in interplanar distances upon heat treatment and indicate an increase in the packing density of macromolecules during thermally activated relaxation.

In this work, we used the concept of controlling the properties of poly(4-methyl-2-pentyne) [PMP] by changing the polymerization conditions. We synthesized PMP using novel NbBr5-and TaBr5-based catalytic systems. PMP obtained with TaBr5-based systems are characterized not only by greater resistance to dissolution, but also by significantly more limited swelling in organic solvents compared to PMP obtained with NbBr5-based catalysts. Solution and solid-state C-13 NMR spectroscopy showed that synthesized PMP samples have a mixed ratio of cis-/trans-units. The X-ray diffraction indicated an increase in the polymer packing density with an increase in the dissolution selectivity, which can be associated not only with the ratio of cis-/trans-units in polymers, but also with the lengths of the sequences of units of the same geometry that influences the polymer conformation. According to the low-temperature argon sorption PMP demonstrates high Brunauer-Emmett-Teller (BET) surface area (up to 846 cm(3)/g). PMP film membranes exhibit a high level of permeability (P-O2 = 1400-2100 barrer for polymers synthesized with NbBr5-based catalysts and P-O2 similar to 1100 barrer for polymers synthesized with TaBr5-based catalysts). This study provides the opportunity of obtaining PMP, combining high permeability with high resistance to organic substances.

The structure of the films of poly(1-trimethylsilyl-1-propyne) (PTMSP) with different configurational compositions (the concentration ofcis-units of 40 to 80%) is analyzed in this study. The combination of X-ray diffraction analysis and atomic force microscopy makes it possible to reveal the peculiarities of the supramolecular organization and morphology of PTMSP films. The diffraction patterns of PTMSP films indicate an increase in the ordering of the supramolecular organization in the case of an increase in the concentration ofcis-units, and the value of the characteristic interchain distance in PTMSP films does not depend on the fraction ofcis-units. According to the data of atomic force microscopy, the surface of PTMSP films is characterized by the presence of cluster-like formations the size of which decreases with the increase in the concentration ofcis-units (from 18.3 nm for PTMSP with the concentration of thecis-units of 40% to 6.8 nm for PTMSP with the concentration ofcis-units of 80%). The decrease in permeability coefficients for O(2)and N(2)with an increase in the concentration ofcis-units in PTMSP correlates with the increase in the ordering of the supramolecular organization and decrease in cluster size. The performed study shows that the structural features of the PTMSP films may be due to the effect of both the configurational composition of macrochains and relaxation processes accompanying the formation of a film obtained by evaporation on a substrate.

This work is devoted to the chemical modification of the polymers of 1,2-disubstituted acetylenes for the creation of gas-separation membranes possessing enhanced stability to aliphatic hydrocarbons and CO 2 selectivity. The feasibility of obtaining polyacetylenes containing chlorine atoms in the side substituents of poly(1-trimethylsilyl-1-propyne) (PTMSP) and poly(4-methyl-2-pentyne) (PMP) by radical chlorination with N -chlorosuccinimide has been shown. The reaction has been carried out under mild conditions to minimize the possibility of polymer degradation and other side reactions. The obtained polymers exhibit good mechanical and film-forming properties as well as high thermal stability. Chlorinated PTMSP possesses enhanced stability to alicyclic and aliphatic C 5 –C 12 hydrocarbons. It has been shown that in the case of introduction of chlorine into the structure of PTMSP and PMP, the CO 2 /N 2 and CO 2 /CH 4 selectivities increase, with the high level of permeability being retained.

In this work, the polymerization of 1-trimethylsilyl-1-propyne [TMSP] using catalytic systems based on pentabromide Nb(V) and Ta(V) with organometallic cocatalysts Ph3Bi, Ph4Sn, Bu4Sn, Ph3SiH, and Et3SiH was investigated. The use of NbBr5-based catalytic systems has strongly marked cis-stereospecificity and gives highly cis-enriched poly(1-trimethylsilyl-1-propyne) [PTMSP] (content of cis-units above 70%), whereas the use of TaBr5-based catalytic systems leads to the formation of PTMSP with mixed cis-/trans-composition (content of cis-units from 50 to 65%).With increasing cis-content, solvent resistance of PTMSP increases significantly. PTMSP with a content of cis-units above 70% obtained on NbBr5-containing systems in cyclohexane acquires resistance to aliphatic and aromatic hydrocarbons, and cis-regular PTMSP obtained on NbBr5-based systems in toluene is totally insoluble in any of the organic solvents. The results of wide-angle X-ray diffraction indicate an increase in the packing density of the polymer during the transition from a mixed configuration to a cis-regular one. Durable PTMSP film membranes exhibit ultra-high permeability coefficients for individual gases (e.g., $${{P}_{{{{{\text{O}}}_{{\text{2}}}}}}}$$ = 8500–11000 barrer, $${{\alpha }_{{{{{\text{O}}}_{{\text{2}}}}{\text{/}}{{{\text{N}}}_{{\text{2}}}}}}}$$ = 1.5–1.9). According to the low-temperature Ar sorption, PTMSP synthesized with NbBr5- and TaBr5-based catalytic systems has high BET surface areas in the range of 870–1050 m2/g, high intrinsic microporosity, and higher gas permeability coefficients of PTMSP correlate with BET surface area growth.

Abstract—The effects of acetylating and deacetylating compounds on the activity of succinate dehydrogenase, as well as on the membrane potential and calcium retention capacity of the isolated liver mitochondria, supported by the oxidation of succinate, has been investigated. The chemical reagent N-acetylimidazole, the microbial metabolite phenylacetate, along with the drugs acetylsalicylic acid and N-acetylcysteine, were used as acetylating compounds. These compounds reduced succinate dehydrogenase activity to different extents depending on the concentration and incubation conditions. An inhibitory analysis using intermediate electron carriers has shown that the ubiquinone-binding site of the enzyme undergoes acetylation. The inhibition was partially eliminated or prevented by pre-incubation of the mitochondria with nicotinamide adenine dinucleotide, a co-factor for deacetylation, and with polyamine spermidine, an acceptor of acetyl groups.

Fluorinated copolymers with different compositions and geometric structures have been prepared from 1-trimethylsilyl-1-propyne and its fluorinated containing analogue 1-(3,3,3-trifluoropropyldimethylsilyl)-1-propyne and then studied. The copolymers combine resistance to different hydrocarbons with high permeability coefficients and high selectivity of n -butane separation from its mixture with the noncondensable hydrocarbon methane. High microporosity of the copolymers is confirmed by the results of the determination of the pore volume and pore surface area using low-temperature sorption of nitrogen and the investigation of the film surface by atomic force microscopy (AFM). It has been found that microporosity, which determines the transport properties of the copolymers, depends on both their comonomer composition and the microstructure formed at the stage of polymer synthesis catalyzed by a certain catalyst system. In particular, the copolymers produced in the presence of a TaCl 5 –Ph 3 Bi catalyst have a greater pore size and a larger pore surface area relative to copolymers with a similar composition formed in the presence of the NbCl 5 –Ph 3 SiH system. The high values of gas transport parameters of the obtained copolymers and their selectivity for recovery of condensable hydrocarbons from vapor–gas mixtures together with resistance to higher hydrocarbons make these copolymers promising membrane materials, e.g., for use in natural gas conditioning processes or separation of C 3+ hydrocarbons from associated petroleum gas.

Disubstituted polyacetylene poly(4-methyl-2-pentyne) (PMP) exhibits one of the highest levels of gas/vapor permeability and selectivity of C3+ recovery from mixtures with permanent gases among known polymers. In this study, semi-interpenetrating networks based on compatible mixtures of PMP and thermally crosslinked polyethyleneimine (PEI) have been obtained to enhance the resistance of PMP to organic solvents. Investigation of the phase equilibrium of PMP and PEI mixtures by optical interferometry has revealed that PMP dissolves up to 30 vol % PEI at room temperature. The fact of thermal crosslinking of PEI is confirmed by IR data. The influence of the proportion of crosslinked PEI on the gas permeability, solubility, and swelling in organic solvents of the films prepared from PMP mixtures with PEI has been examined. Having the PEI content higher than 20 vol %, the films are resistant to organic solvents for at least 14 days. Moreover, with an increase in the proportion of PEI, the degree of swelling of the films is substantially reduced. The increase in stability can be explained by the retention of PMP macromolecules in the crosslinked PEI matrix, which probably reduces the swelling of the films and impedes the extraction of linear PMP macromolecules from the polymer network. The ideal O-2/N-2, CO2/N-2, and CO2/CH4 selectivities increase with a growth in the PEI proportion.

The phase equilibrium and rheological properties of poly(1-trimethylsilyl-1-propyne) solutions obtained with tantalum catalysts are studied. For three polymers with different molecular masses, phase diagrams are determined in a number of solvents. From these diagrams, the Hansen solubility parameters of poly(1-trimethylsilyl-1-propyne) are calculated by the method proposed in this work. Dilute solutions of poly(1-trimethylsilyl-1-propyne) behave as Newtonian liquids, whereas the viscosity of viscoelastic concentrated systems decreases as the shear rate grows. The molecular and rheological characteristics of studied poly(1-trimethylsilyl-1-propyne) samples are compared with the samples prepared with NbCl5 catalysts. Poly(1-trimethylsilyl-1-propyne) obtained with a catalytic system involving tantalum pentachloride is characterized by high intrinsic viscosity and solution viscosity compared to poly(1-trimethylsilyl-1-propyne) prepared with niobium catalyst. The difference in properties is due to the dissimilar ratios of cis and trans units in the samples.