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The main purpose of this paper is to compare the chromatographic properties of capillary columns prepared with polymers with different backbone structures and to demonstrate the possibility of polymer differentiation via inverse gas chromatography. With the use of addition and metathesis types of polymerization of tricyclononenes, two new stationary phases were prepared. The metathesis polymer contained double bonds in the polymeric backbone while the backbone of the addition polymer was fully saturated and relatively mobile. A comparison of the separation and adsorption properties of new phases with conventional gas chromatography (GC) stationary phases clearly indicated their non-polar characteristics. However, the difference in the polymer structure appeared to have very little effect on the stationary phase separation properties, so other parameters were used for polymer characterization. The thermodynamic parameters of the sorption of alkanes and aromatic compounds in both polymeric stationary phases were also very similar; however, the entropy of sorption for hydrocarbons with seven or more carbon atoms was different for the two polymers. An evaluation of the specific surface energy of the stationary phases also allowed us to discriminate the two stationary phases.

The interest in porous organic materials derived from norbornenes is driven by versatile chemistry of norbornenes, fine-tunable structure of these polymers, high accessible surface area, and large ...

Polynorbornenes are ideal materials for systematic structure–property investigations designed to correlate gas-transport properties to polymer structure. The modular nature of norbornene-based systems provides a facile route towards the synthesis of diverse polymeric materials. Though many valuable correlations between gas-permeability and polynorbornene structure have been summarized in a prior review (2017), many of these efforts focused heavily on the design of materials with high permeabilities. More recently, the design of next-generation polynorbornene membranes has shifted toward the development of materials that are highly selective for multiple targeted gas separations. Since 2017, tremendous progress has been realized in the preparation of stable and highly selective polynorbornenes for membrane-based gas separations. Examples include polynorbornene derivatives that exhibit very high selectivity for CO2/N2 and light hydrocarbon (e.g., C3+/C1) separations, some of which exhibit gas separation performances that approach or exceed the 2008 upper bound. Herein, we summarize prior findings, present recent developments in the field of advanced polynorbornene membrane materials for targeted gas separations, and provide an outlook for the future of this field of research.

5-(Methoxymethyl)norbornene is synthesized from the commercial 5-norbornene-2-methanol via the Williamson reaction. Its addition polymerization is studied, and conditions for formation of a high molecular weight product with a high yield are determined. The gas-transport properties of the synthesized addition polynorbornene for a wide set of gases (He, H2, O2, N2, CO2, CH4) are investigated. Our data make it possible to infer that the ether group in the side chain of polynorbornenes affects their gas-transport properties. It is shown that the ether group contributes to a reduction in the level of gas permeability and an increase in the selectivity of separation of gas pairs CO2/N2 and CO2/CH4.

A comprehensive interdisciplinary study is performed for 12 polymers promising for the fabrication of membranes for extracorporeal membrane oxygenation based on them by methods of gas permeability, wetting, piezoelectric microweighing, and direct biomedical methods for determining hemocompatibility of whole blood from healthy donors. It is found that trimethylsilyl-substituted polytricyclononene, polyhexafluoropropylene, and semicrystalline polyphenylene oxide are the best polymer materials for the diffusion membranes of oxygenators. It is shown that traditional approaches that associate the surface properties of polymers (water wettability, plasma protein adsorption, energy characteristics of surfaces) with their hemocompatibility do not provide precise correlations with the biomedical methods based on the analysis of the changes in the shape of blood cells as a result of adhesion on the surface of the polymer. The complexity of the mechanism of interaction of the surface of polymers with blood also does not allow for clear structure–property correlations traditional for membrane gas separation. The directions of further research in this area are defined.

For the first time, dielectric and calorimetric investigations of a homologous series of Janus polynorbornenes with rigid main backbones and flexible −Si(OR)3 side groups of differing length alkyl ...

The molecular dynamics of addition-type poly(tricyclononenes) with Si-substituted bulky side groups has been investigated by a combination of neutron time-of-flight and neutron backscattering spectroscopy methods on a time scale from 0.1 ps to ca. 3 ns. The investigated poly(tricyclononenes) PTCNSi1 and PTCNSi2g both bear a high microporosity which makes them promising candidates for active separation layers for gas separation membranes. At least for larger gas molecules it is assumed that the pathways for diffusion require an enlargement of pre-existing micropores in terms of an activated zone. A low temperature relaxation process was found for both polymers by the performed neutron scattering experiments. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized. For PTCNSi1 (3 methyl groups in the monomeric unit) it was found that all methyl groups take part in the methyl group rotation whereas for PTCNSi2g (6 methyl groups in monomeric unit) a considerable number of methyl groups are blocked in their rotation. This immobilization of methyl groups is due to the sterically demanding arrangement of the methyl groups in PTCNSi2g. This conclusion is further supported by the result that the activation energy for the methyl group rotation is three times higher for PTCNSi2g than that of PTCNSi1.

Inelastic incoherent neutron time-of-flight scattering was employed to measure the low frequency density of states for a series of addition polynorbornenes with bulky side groups. The rigid main chain in combination with the bulky side groups give rise to a microporosity of these polymers in the solid state. The microporosity characterized by the BET surfaces area varies systematically in the considered series. Such materials have some possible application as active separation layer in gas separation membranes. All investigated materials show excess contributions to the Debye type density of states characteristic for glasses known as Boson peak. The maximum position of the Boson peak shifts to lower frequency values with increasing microporosity. Data for PIM-1 and Matrimid included for comparison are in good agreement to this dependency. This result supports the sound wave interpretation of the Boson peak.

The addition polymerization of a norbornene derivative containing silatrane group is studied for the first time. It is demonstrated that a saturated polymer based on this monomer can be synthesized in the presence of Pd and Ni catalysts. The polymerization conditions under which polymers are formed in a high yield are found. The polymers obtained are insoluble, heat resistant, and amorphous. The physicochemical properties of the synthesized polymer are investigated.

A series of addition copolymers of 3-trimethylsilyltricyclo[4.2.1.02.5]non-7-ene with a bifunctional comonomer—2,5-norbornadiene dimer—are synthesized. It is shown that, with the introduction of a small amount of the 2,5-norbornadiene dimer (up to 0.3 mol %), the molecular weight of the polymer increases. When using a large amount of the 2,5-norbornadiene dimer, crosslinked insoluble polymers are formed. As exemplified by a copolymer containing 0.3 mol % 2,5-norbornadiene dimer units, the introduction of the bifunctional comonomer does not lead to a significant decrease in gas permeability, and the developed method can be used to increase the molecular weights of polymers, improve their mechanical properties, and make polymers resistant against plasticization.

The nature of micropore size distribution in a number of amorphous polymer glasses (membrane materials and sorbents) has been discussed on the basis of data on positron annihilation lifetime spectroscopy (PALS) and low-temperature CO2 gas sorption (LTGS). The LTGS (CO2) technique in combination with mathematical processing by the density functional theory gives a multimodal size distribution of micropores in the range of effective diameters of 0.5–1.5 nm for PIM-1 type polymers of intrinsic microporosity. The positron annihilation data (time distribution of annihilation emission events) are also satisfactorily processed under the assumption of multimodality. The results have been discussed in terms of the “local rigidity” of the materials under consideration.

Two metathesis homopolymers with tri(n-propoxy)silyl and tri(n-butoxy)silyl side substituents are synthesized, and their adhesive properties are investigated. High-molecular-weight polymers are prepared in the presence of the first-generation Grubbs catalyst in a good yield. Adhesive properties are studied by the probe tack method at different temperatures. Using the example of the studied polymers, for the first time, it is shown that pressure-sensitive adhesives can be obtained on the basis of polynorbornenes. The effect of the length of the side silicon substituent on the work of adhesion is evaluated.

A new metathesis polynorbornene containing bulky and reactive silatrane side groups is synthesized, and its gas-transport properties are investigated. The metathesis polymerization of 3-silatranyltricyclo[ 4.2.1.02.5]non-7-ene is conducted in the presence of the first-generation Grubbs catalyst. The homopolymer is obtained with a nearly quantitative yield of 98% and a molecular mass of Mw = 1.3 × 106 (Ð = 3.7). According to X-ray phase analysis, the homopolymer is amorphous and its glass-transition temperature is 232°С (DSC). The gas permeability of the metathesis polymer for a set of gases, including He, H2, O2, N2, CO2, and CH4, is investigated, and the corresponding diffusion and solubility coefficients are determined.

Silicon-substituted polynorbornenes are an unusual class of polymeric membrane materials, combining the properties of both glassy and rubbery polymers. They exhibit an attractive performance for CO2/N2 separation and for separation of gaseous hydrocarbons. However, addition polynorbornenes with Si-groups (for examples, having Si–O–C, or Si–O–Si-spacers) often suffer from poor film-forming properties due to low molecular weights of the polymers. Herein, by using a new simple and efficient approach to the synthesis of such polymers, we prepared two sets of novel high-molecular-weight polymers based on pure exo-isomers of Si-containing norbornenes and studied their gas transport properties in detail. The desired metathesis and addition polynorbornenes with (C2H5)3Si-, (CH3)3SiO(CH3)2Si- and ((CH3)3SiO)2(CH3)Si-side groups were readily obtained in good or high yields via selective hydrosilylation of norbornadiene-2,5 by commercial silanes followed by polymerization over Ru- or Pd-catalyst. Diffusion (D) and permeability (P) coefficients of these polynorbornenes were determined for permanent gases (He, H2, O2, N2, CO2) and C1–C4 alkanes. The influence of exo-/endo-orientation of substituents on gas transport properties and the relationship between nature of side-groups and membrane properties were evaluated. The data on BET, SEM, WAXD, and fractional free volumes of the polymers are also reported and discussed.

A series of polymers of a new type, which contain rigid polymer main chains (glassy nature) and long flexible side substituents (rubbery nature), were prepared from norbornene derivatives with (AlkO)3Si-groups of a different length (Alk = Me, Et, n-Pr, n-Bu) as promising materials for membrane separation of gaseous hydrocarbons. The 1st generation Grubbs complex and Pd–N-heterocyclic carbene complex in combination with Na+[(3,5-(CF3)2C6H3)4B]− and PCy3 were used as catalysts of metathesis and addition polymerization in the synthesis of high-molecular weight polymers (Mw ≤ 1.1 × 106) with good or high yields (up to 99%). The prepared addition polymers were glassy, while the glass transition temperature of metathesis polymers depended on the length of the alkyl-group in (AlkO)3Si-substituents and it varied in the range of −44 to 61 °C. The dramatic tuning of polymer gas-transport properties was demonstrated by the change of the polymer main chain structure and the length of tri(n-alkoxy)silyl side groups. For example, we have succeeded for the first time in obtaining metathesis polynorbornenes, which turned out to be more permeable than their addition isomers. Not being large free volume polymers, all studied metathesis and addition polytricyclononenes exhibited solubility controlled permeation of hydrocarbons (P(n-C4H10) up to 8100 barrer) and high C4/C1 selectivity (22–49).

New norbornene type monomer bearing reactive triethoxysilyl group was synthesized, and its addition homo- and copolymerization with 3-trimethylsilyltricyclonon-7-ene was studied. The target monomer was obtained using regio- and stereospecific [2σ+2σ+2π] cyclo-addition of quadricyclane with vinyltrichlorosilane followed by the reaction of the formed cycloadduct with ethanol in the presence of triethylamine. Addition polymerization was investigated over the three-component Pd-containing catalytic system (Pd complex, Na+[B(3,5-(CF3)2C6H3)4]–(cocatalyst) and tricyclohexylphosphine). The N-heterocyclic carbene Pd complex (SIPrPd(cinn)Cl) with high activity and tolerance to the Si—O—C moieties was used as a catalyst. The yields of the homo- and copolymers were 24—68% depending on the monomer (comonomer): Pd: B: PCy3 ratio. The obtained addition polymers are high-molecular-weight amorphous products, the glass transition temperature of which exceeds 300 °C. The presence of reactive Si(OC2H5)3 groups in the homo- and copolymers made it possible to carry out a hard-to-realize cross-linking involving side substituents and followed by the formation of insoluble polymers.

A simple one-step approach for the selective synthesis of exo-norbornenes with organosilicon substituents is suggested through the direct hydrosilylation of norbornadiene-2,5 with chlorine-free silanes. Using the example of norbornadiene-2,5 hydrosilylation with pentamethyldisiloxane and 1,1,1,3,5,5,5-heptamethyltrisiloxane, the possibility of obtaining exo-isomers of norbornenes with 100 exo-/endo-selectivity is shown. The investigation of Pt-, Rh-, and Pd-complexes in combination with various ligands as catalysts was performed. The hydrosilylation of norbornadiene-2,5 in the presence of Pt- or Rh-catalysts was not selective and led to a mixture consisting of three isomers (exo-/endo-norbornenes and substituted nortricyclane). In the case of the Pd-salt/ligand catalytic system, the formation of an endo-isomer was not observed at all and only two isomers were formed (exo-norbornene and nortricyclane). The selectivity of exo-norbornene/nortricyclane formation strongly depended on the nature of the ligand in the Pd-catalyst. The best selectivity was revealed when R-MOP was the ligand, while the highest catalytic activity was reached with a dioxalane-containing ligand.

Structure-property study of polynorbornenes for low dielectric permittivity materials was performed. Dielectric properties of various polynorbornenes bearing F-, Si- and alkenyl-side groups were investigated. The incorporation of both fluoroorganic- and Me3Si-groups as side substituents was found to be a fruitful tool to tune dielectric properties and to obtain polymeric materials with low values of dielectric relative permittivity (hereinafter dielectric permittivity) and the dissipation factors. Addition polynorbornenes with Me3Si- or alkenyl-side groups disclosed dielectric permittivity in the range of 2.07–2.34. Polynorbornenes containing fluouroorganic groups exhibited dielectric permittivity as low as 1.94–2.78. To the best of our knowledge, the achieved values of dielectric permittivity are the lowest ones among published for polynorbornenes. The investigated polymers also exhibited low or moderate values of the dissipation factor. The obtained results are considered and discussed along with the data of wide-angle X-ray diffraction, positron annihilating lifetime spectroscopy, low temperature nitrogen adsorption/desorption investigations.

In the paper porous polymeric materials recently obtained from norbornene derivatives are presented. Up to now three groups of polynorbornenes exhibited the presence of micro-either mesopores and large surface area are considered. The first one is the group of Me3Si-containing addition polynorbornenes. These polymers are microporous and possess Brunauer-Emmett-Teller (BET) surface area up to 800 m2/g. The second group includes polynorbornenes with carbocycles in the side polymer chains. Up to now, only polydicyclopentadiene is reported as porous material from this group. The third group includes polymers based on bifunctional norbornenes. These polymers have demonstrated tunable porous properties and large BET surface area up to 1000 m2/g.

Sorption and membrane properties of metathesis and addition polymers based on 5-(2’-norbornanyl)- norbornene were studied. The desired monomer was prepared from 5-vinyl-2-norbornene by its selective hydrogenation to 2-vinylnorbornane followed by Diels-Alder reaction with dicyclopentadiene. Metathesis polymer was prepared in the presence of the first generation Grubbs catalyst. Addition polymerization was realized using a three component catalytic system consisting of Pd(OAc)2 (precatalyst), NaBARF (cocatalyst, Na+[B(3,5-(CF3)2C6H3)4]-) and a phosphine (tricyclohexylphosphine). The prepared polymers are high-molecular-weight, glassy and amorphous products. The polymers were isolated in good or high yields. Both synthesized metathesis and addition polymers showed good solubility in common organic solvents and thin, robust films were readily prepared via the solution casting method. The performed preliminary investigations showed that it is possible to obtain polymeric materials possessing large BET surface area (up to 500-700 m2/g) and promising gas-transport properties from norbornene derivatives with bulky and rigid carbocyclic groups.

New microporous homopolymers were readily prepared from norbornadiene-2,5, its dimer and trimer by addition (vinyl) polymerization of the corresponding monomers with 60&ndash, 98% yields. As a catalyst Pd-N-heterocyclic carbene complex or Ni(II) 2-ethylhexanoate activated with Na+[B(3,5-(CF3)2C6H3)4]&minus, or methylaluminoxane was used. The synthesized polynorbornenes are cross-linked and insoluble. They are glassy and amorphous polymers. Depending on the nature of the catalyst applied, BET surface areas were in the range of 420&ndash, 970 m2/g. The polymers with the highest surface area were obtained in the presence of Pd-catalysts from the trimer of norbornadiene-2,5. The total pore volume of the polymers varies from 0.39 to 0.79 cm3/g, while the true volume of micropores was 0.14&ndash, 0.16 cm3/g according to t-plot. These polymers gave CO2 uptake from 1.2 to 1.9 mmol/g at 273 K and 1 atm. The porous structure of new polymers was also studied by means of wide-angle X-ray diffraction and positron annihilation lifetime spectroscopy.

Herein we report a new approach to cross-link substituted addition polynorbornenes. The cross-linking was realized by the copolymerization of SiMe3-containing tricyclononene with low amounts of tricyclononene bearing triethoxysilyl groups followed by the hydrolysis of Si(OEt)3-groups with the formation of interchain siloxane bonds. The amount of cross-links proved to depend on the composition of copolymers and cross-linking conditions, which allowed to perform controlled cross-linking of polynorbornenes. The insoluble polymers with good film forming properties were obtained by cross-linking. The developed method could find further application for the modification of polynorbornenes.

In this work we report the synthesis and polymerization of new norbornenes containing trialkoxysilyl groups. These monomers were reactive both in ROMP and in addition polymerization. Obtained polymers possessed interesting properties. So despite of low surface area they were good permeable, and some of them exhibited a low tendency to aging. The solubility controlled selectivity for hydrocarbons was observed. These properties would allow finding industrial application of obtained polymers for the membrane gas separation of hydrocarbon mixtures.

Correction for ‘The selective hydrosilylation of norbornadiene-2,5 by monohydrosiloxanes’ by Marina A. Guseva et al., RSC Adv., 2019, 9, 33029–33037.

Consequitive treatment of quadricyclane with trichlorovinylsilane and methanol affords 3-trimethoxysilyltricyclo[4.2.1.02,5]non-7-ene which on reaction with triethanolamine gives a new silatrane promising as a gas separation membrane material.