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The reaction of 1,3,5,7-cyclooctatetraene with silicon-substituted ethylenes has been studied for the first time. It is shown that vinyltrimethylsilane is inactive in the reaction, and vinyltrichlorosilane forms 7-trichlorosilyltricyclo[4.2.2.02,5]deca-3,9-diene in up to 12% yield. A new silicon-substituted monomer 7‑trimethylsilyltricyclo[4.2.2.02,5]deca-3,9-diene containing 92% of the endo-isomer has been synthesized by methylation of the chloroadduct. The metathesis polymerization of the final monomer mediated by the Grubbs Ru catalysts of the first and second generations is studied. A new poly(7-trimethylsilyltricyclo[4.2.2.02,5]deca-3,9-diene) containing a bulky bicyclic fragment and predominantly trans-double bonds in the main chain (up to 94%) is obtained in 90–96% yields. The polymer is characterized by the highest glass transition point (187°C) in the series of monotrimethylsilyl-substituted polynorbornenes. The double bonds present in the monomer unit open up prospects for further modification.

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.

New copolymers of norbornene and 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane containing flexible siloxane and rigid norbornene fragments in the main chain are synthesized. Synthesis is carried out using three types of olefin metathesis reactions: the ring-opening metathesis polymerization of norbornene, the metathesis of nonconjugated diene 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane, and the interchain macromolecular cross-metathesis between polynorbornene and siloxane-containing polyene. The latter reaction is studied for the first time. With its help, new statistical multiblock copolymers of norbornene and 1,5-bis(hexenyl-5)-1,1,3,3,5,5-hexamethyltrisiloxane with different average block lengths are obtained and characterized by 1H and 13C NMR and IR spectroscopy. The effect of the copolymer structure on their thermal properties is investigated.

The problems of the processing of waste polymers of the main types are considered. Particular attention is paid to works related to the use of modern waste conversion methods for the production of motor fuels and valuable petrochemicals. The processes of thermal and catalytic cracking, hydroconversion, and polymer metathesis are discussed in detail.

Fluorinated polymers are attractive due to their special thermal, surface, gas separation, and other properties. In this study, new diblock, multiblock, and random copolymers of cyclooctene with two fluorinated norbornenes, 5-perfluorobutyl-2-norbornene and N-pentafluorophenyl-exo-endo-norbornene-5,6-dicarboximide, are synthesized by ring-opening metathesis copolymerization and macromolecular cross-metathesis in the presence of the first- to third-generation Grubbs’ Ru-catalysts. Their thermal, surface, bulk, and solution characteristics are investigated and compared using differential scanning calorimetry, water contact angle measurements, gas permeation, and light scattering, respectively. It is demonstrated that they are correlated with the chain structure of the copolymers. The properties of multiblock copolymers are generally closer to those of diblock copolymers than of random ones, which can be explained by the presence of long blocks capable of self-organization. In particular, diblock and multiblock fluorine-imide-containing copolymers show a tendency to form micelles in chloroform solutions well below the overlap concentration. The results obtained may be of interest to a wide range of researchers involved in the design of functional copolymers.

Commercial metathesis polynorbornene is used for the fabrication of high-damping coatings and bulk materials that dissipate vibration and impact energies. Functionalization of this non-polar polymer can improve its adhesive, gas barrier, and other properties, thereby potentially expanding its application area. With this aim, the post-modification of polynorbornene was carried out by inserting ethylene–vinyl acetate–vinyl alcohol blocks into its backbone via the cross-metathesis of polynorbornene with poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers. For the first time, epoxy groups were introduced into the main chains of these copolymers, followed by the oxirane ring opening reaction. The influence of post-modification on the thermal, gas separation, and mechanical properties of the new copolymers was studied. It was shown that the gas permeability of the copolymer significantly depends on its composition, as well as on the amounts of hydroxyl and epoxy groups. The developed methods efficiently improve the barrier properties, reducing the oxygen permeability by 15–33 times in comparison with polynorbornene. The obtained results are promising for various applications and can be extended to a broader family of polydienes and other polymers containing backbone double bonds.

New norbornene-based functional multiblock copolymers containing ethylene–vinyl acetate/vinyl alcohol sequences are synthesized via the olefin cross-metathesis reaction of polynorbornene with poly(5-acetoxy-1-octenylene) followed by CC bond hydrogenation and acetoxy group deprotection. Macromolecular cross-metathesis, a recently developed type of interchange reaction, was carried out in the presence of Grubbs’ ruthenium catalysts and monitored by in situ1H NMR and ex situ13C NMR spectroscopy. This results in copolymer formation and its gradual randomization by segment reshuffling promoted by polymer-based Ru-carbenes. The kinetic study reveals that, despite the presence of bulky acetoxy substituents in polyoctenamer chains, Grubbs’ catalyst interacts with them more easily than with polynorbornene chains, which have cyclopentane rings in the backbone. The rate of the subsequent interchange reaction is controlled by the interaction of [Ru]-poly(5-acetoxy-1-octenylene) carbenes with norbornene units. It is found that the acetoxy groups markedly slow down the interaction of [Ru]-polynorbornene carbenes with the CC bonds in octenamer units. Since these carbenes are relatively unstable, they cause a noticeable decay of the reaction active centers. Our study demonstrates that the chain structure and, therefore, physico-chemical characteristics of multiblock copolymers can be tailored by adjusting the cross-metathesis conditions, such as the polymer concentration, polymer to catalyst ratio, and reaction time. Polymer-analogous reactions of hydrogenation and deacetylation transform octenamer units into ethylene–vinyl acetate/vinyl alcohol segments and thus open up more possibilities for tuning the thermal, gas barrier, and hydrophobic/hydrophilic properties of the synthesized norbornene-based multiblock copolymers.

The expansion of the range of available and reactive monomers allowing preparation of novel polymeric materials, is an actual task of polymer chemistry. This mini-review is devoted to the polymerization of tricyclo [4.2.1.02,5]non-7-enes (tricyclononenes) and tricyclo[4.2.1.02,5]nona-3,7-dienes (tricyclonona-dienes)–norbornene type monomers containing norbornene and cyclobutane or cyclobutene fragments in the molecules. Their synthesis is carried out using available cyclopentadiene or quadricyclane, which is a product of norbornadiene photo-isomerization. The features of ring-opening metathesis and addition polymerization of tricyclononenes with participation of double bond in the norbornene fragment are highlighted. Examples of the polymerization of a wide range of tricyclononenes with F-, Si-, O-, and N-containing substituents have demonstrated that they are noticeably more active monomers than norbornenes with the same substituents. The main successes have been achieved in the synthesis of F- and Si-substituted polytricyclononenes, which are promising materials for lithography and membrane gas separation.

The activity of known and newly synthesized Ru-carbene catalysts in the metathesis polymerization of 1,5-cyclooctadiene and interchain cross-metathesis of synthesized polybutadiene with polynorbornenes is studied. First- and second-generation Grubbs Ru-complexes, second-generation Hoveyda–Grubbs complexes, and their modified analogs with asymmetric fluoro-containing ligands and unsaturated imidazolyl moieties are used as catalysts. It is shown that in the presence of the second-generation modified and nonmodified catalysts a partially crystalline polybutadiene is formed, in which blocks with trans-С=С bonds are about four times longer than blocks containing cis-С=С bonds. In the case of catalysts with bulkier ligands, the length of trans blocks is smaller and the melting temperature of the polymer is lower. The activities of the catalysts are compared by in situ 1Н NMR monitoring. New norbornene-butadiene multiblock copolymers are prepared for the first time by cross-metathesis between polybutadiene and polynorbornene. The highest degree of blockiness of the copolymers is attained when using second-generation Grubbs and Hoveyda–Grubbs catalysts. The activity sequences for the studied catalysts are constructed. It is shown that macromolecular cross-metathesis occurs more intensively in the presence of the catalysts with less bulky ligands.

Previously, it was shown that the presence of bulky silicon-containing substituents in the monomer unit of metathesis polynorbornenes hinders the postmodification and, in particular, exhaustive gem-difluorocyclopropanation of main-chain double bonds. In order to reduce the double bonds shielding by substituents, a new polynorbornene with a dimethylsilacyclopentane fragment in the monomer unit, poly(4,4-dimethyltricyclo[5.2.1.02,6]-4-siladec-8-ene) (PNBCP), is synthesized, in which the silylmethyl group is moved further from the double bonds. In order to achieve this, the monomer 4,4-dimethyltricyclo[5.2.1.02,6]-4-siladec-8-ene (NBCP) is first obtained via the diene condensation of 1,3-cyclopentadiene and 1,1-dichlorosilacyclopent-3-ene with following methylation of Si-Cl bonds. NBCP is polymerized by the ring-opening metathesis scheme in the presence of the first-generation Grubbs catalyst, Cl2(PCy3)2Ru=CHPh. The new polymer PNBCP is obtained in a yield of 99–100% and characterized. The gem-difluorocyclopropanation of PNBCP with difluorocarbene, generated during the thermolysis of sodium chlorofluoroacetate, is studied; the conditions for exhaustive replacement of double bonds by gem-difluorocyclopropane are found. It is shown that PNBCP is more active in postmodification compared to poly(5-trimethylsilyl)norbornene but is less active than unsubstituted polynorbornene. It is demonstrated that the introduction of the silacyclopentane fragment into the monomer unit of the metathesis polynorbornene and its subsequent difluorocyclopropanation lead to increase in gas permeability and diffusion and cause a slight decrease in ideal separation selectivities. It is found that gem-difluorocyclopropanation increases the glass transition temperature of PNBCP by 60°C and makes its films stable when stored in air.

The reaction of macromolecular cross-metathesis of polynorbornene and polydodecenamer catalyzed by the first-generation Grubbs Ru-carbene complex is studied for the first time. Polydodecenamer with high-molecular-weight characteristics (Mw = 406 × 103, Ð = 2.5) and a yield of 96% is synthesized by the ring-opening metathesis polymerization of cyclododecene mediated by the second-generation Grubbs catalyst. The polymer has a melting temperature of 62–83°C, depending on the content of trans double bonds, and shows poor solubility in organic solvents at room temperature. Its cross-metathesis with polynorbornene at 40°С gives rise to new statistical multiblock copolymers of norbornene and cyclododecene with different degree of blockiness. NMR, GPC, and DSC were used to investigate the effect of reaction conditions on the structure and thermal properties of the copolymers. At the initial step of the reaction, along with a high-molecular-weight peak, the GPC chromatograms exhibit a peak due to the low-molecular-weight fraction (M = (1–2) × 103), suggesting the formation of cyclooligomers. With increasing degree of interchain exchange, the proportion of the oligomeric fraction decreases appreciably. The kinetics of the cross-metathesis of polynorbornene with polydodecenamer and polyoctenamer at 40°С is studied by in situ 1Н NMR spectroscopy and ex situ 13С NMR spectroscopy. The rates of elementary reactions in these blends differ insignificantly, except for the conversion stage of the initial carbenes into polymer ones. The formation rate for carbene [Ru]=polyoctenamer is three times higher than the formation rate for the [Ru]=polydodecenamer carbene. In both cases, the fraction of Ru carbenes attached to norbornene units is extremely small throughout the process.

The macromolecular reaction of interchain cross-metathesis between polynorbornene and poly(5,6-epoxy-1-octenamer) in the presence of the first-generation Grubbs catalyst is studied. Chemically stable poly(5,6-epoxy-1-octenamer) is obtained through metathesis polymerization of 5,6-epoxycyclooct-1-ene with the second-generation Grubbs ruthenium catalyst. New random multiblock copolymers of norbornene and 5,6-epoxycyclooct-1-ene with different average block lengths determined by the reaction time, solvent type, and concentrations of the catalyst and initial homopolymers are synthesized and characterized by NMR, GPC, and DSC. Despite a distance between the epoxy substituent and the reaction center (double bond), poly(5,6-epoxy-1-octenamer) shows a lower activity in the cross-metathesis reaction with polynorbornene compared to unsubstituted polyoctenamer. The influence of epoxy groups present in the backbones of homopolymer and norbornene–cyclooctene multiblock copolymers on their thermal characteristics is studied. It is shown that the glass transition and melting temperatures increase with the concentration of epoxy groups upon the incorporation of an oxirane fragment into both homopolymers and copolymers. The crystallinity of poly(5,6-epoxy-1-octenamer) increases with the content of trans-С=С bonds in the polymer.

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

The methods for synthesis of promising norbornene monomers from norbornadiene and quadricyclane are summarized. A strategy for their synthesis is discussed, combining theoretical and experimental approaches to the selection of catalysts and the conditions for carrying out stereoselective reactions. The mechanisms of catalytic reactions of synthesis of norbornene monomers, as well as the progress in the macromolecular design of functional polymeric materials based on them, are considered. The data on industrial processes of production of polynorbornenes and areas of their use are presented. The bibliography includes 297 references.

An exchange reaction of cross-metathesis between polynorbornene and poly(5-hydroxyoctenamer) in a chloroform–methanol mixture (10: 1 vol/vol) in the presence of Ru–carbene Grubbs’ complexes Gr-1 and Gr-2 has been studied. Gr-2 catalyst has a much higher activity and allows one to obtain multiblock copolymers, which cannot be synthesized directly from norbornene and 5-hydroxy-1-cyclooctene. The average length of the copolymer blocks varies in a wide range depending on the reaction conditions. The individual stages of the process have been studied with the use of in situ monitoring of transformations of Ru–carbene complexes by 1Н NMR spectroscopy and ex situ analysis of heterodyad evolution in copolymers via 13C NMR spectroscopy. As has been shown, poly(5-hydroxyoctenamer) forms Ru–carbene complexes with the catalyst more easily than polynorbornene; in this case, the incorporation of a substituent in the monomer unit of octenamer retards the polymer cross-metathesis. It has been found that, in systems containing Gr-2 and hydroxyoctenamer blocks, the formed ruthenium hydride complexes initiated hydrogenation process. The hydrogenation results in the appearance of crystallinity in the initially amorphous polymers, which opens up the possibilities for the targeted control of the multiblock copolymers properties.

The epoxidation of double bonds in random multiblock copolymers of norbornene and cyclooctene is studied for the first time. The initial copolymers with different composition and average block length are synthesized via the cross-metathesis reaction between polynorbornene and polycyclooctene in the presence of the first-generation Grubbs catalyst. New multiblock copolymers containing oxirane fragments in the backbone are obtained with a yield of 85–92% through epoxidation conducted under the action of m-chloroperbenzoic acid in toluene. The kinetics of epoxidation of polynorbornene, polycyclooctene, and their multiblock copolymers in deuterochloroform and deuterobenzene is investigated via the in situ monitoring of transformation of double bonds using 1Н NMR spectroscopy. It is shown that on the whole the modification of cyclooctene units occurs more easily in copolymers than that in the homopolymer. The thermal properties of epoxidized homo- and copolymers are examined. It is found that upon epoxidation the glass-transition temperature and the melting temperature of multiblock copolymers increase by 40–50 and 20–30°С, respectively, wherein the degree of crystallinity and the temperature of melting grow with the length of the cyclooctene block.

The impact of double bond modification by gem-difluorocyclopropanation (gDFC) in poly(norbornenes) backbone on their gas transport properties was studied for the first time. With this aim the research of gDFC of polynorbornene (PNB) and poly(5-trimethylsilylnorbornene) (PNBSi) in the conditions of sodium chlorodifluoroacetate thermolyses at 180–190 °C in methyl benzoate solution were carried out. The starting poly(norbornenes) were synthesized via ring-opening metathesis polymerization of the corresponding monomers mediated by the first generation Grubbs’ catalyst. The degree of double bonds conversion into the gem-difluorocyclopropane and the molecular weight of modified polymers could be controlled by adjusting the reaction time, sodium chlorodifluoroacetate amount, and polymer concentration in reaction mixture, as well as by addition of inhibitor. The bulky Me3Si-substituent hindered the modification of double bonds in poly(norbornenes)’ backbone. The gDFC decreased the thermal stability of poly(norbornenes). However, the films of modified polymers demonstrated high stability during storage at the ambient conditions, especially in comparison with unmodified polynorbornene. The introduction of gem-difluorocyclopropane in poly(norbornenes) backbone increased their gas permeability coefficients P especially strongly for PNB. Simultaneously the values of ideal selectivity αij = Pi/Pj were not changed or slightly increased. The noted growth of P was caused by increases in the solubility coefficients S. To elucidate the role of the two types of modification fragment ( CF2 and O ) of double bonds a sample was prepared that included both types of the fragments. It was distinguished by increased P and αij values. So, a new and simple approach improving the gas permeation properties of metathesis polynorbornenes was developed. It may be extendable to broader families of polydienes and other polymers containing double bonds in the backbone.

The effect of postpolymerization epoxidation of metathesis polynorbornenes on their gas-transport behavior is studied. For two polymers, unsubstituted polynorbornene and poly(trimethylsilylnorbornene), postpolymerization modification via double bonds is implemented by epoxidation under the action of m-chloroperbenzoic acid to high conversions (95–100%). For initial polymers and their epoxidation products, the permeability and diffusion coefficients are measured and the solubility coefficients are estimated. It is shown that, for both initial polymers, functionalization leads to a marked reduction in permeability (by a factor of 2–10) and diffusion coefficients (by a factor of 3–10); simultaneously, the separation factors increase by a factor of 2–6. Although for all gases the solubility coefficients decrease as a result of epoxidation, the coefficients of CO2 solubility in both epoxidated polymers increase. This effect may be explained by specific interactions of a СО2 molecule possessing the quadrupole moment with С–О–С bonds appearing in a polymer.

The cross-metathesis reaction between polytrimethylsilylnorbornene and polycyclooctene is investigated for the first time. Using the Grubbs Ru-carbene complex of the first generation, the synthesis of random multiblock copolymers of trimethylsilylnorbornene and cyclooctene is carried out. The effect of the reaction conditions on the block length and thermal and crystalline properties of new copolymers is studied by NMR, GPC, and DSC methods. With the use of in situ 1Н NMR spectroscopy, the kinetics of the crossmetathesis reaction is investigated. As for unsubstituted polynorbornene (Polym. Sci., Ser. B 58, 292 (2016)), the catalyst interacts initially with polycyclooctene, giving a polymer carbene complex [Ru]=PCO. Further, this complex attacks the polytrimethylsilylnorbornene chain via cross reaction with formation of complex [Ru]=PNB-Si and a diblock copolymer of trimethylsilylnorbornene and cyclooctene as reaction products. The subsequent cross reactions form a multiblock copolymer with gradually increasing block length. Throughout the entire process, the concentration of [Ru]=PCO exceeds the concentration of [Ru]=PNB-Si by more than two orders of magnitude. Simultaneously, the total concentration of carbene complexes decreases in time through their decay. The reaction kinetics is satisfactorily described by a model proposed previously for interaction between polycyclooctene and polynorbornene.

Crystallinity of statistical multiblock copolymers of norbornene and cyclooctene with nearly equimolar composition and different degrees of blockiness is studied by differential scanning calorimetry including thermal fractionation by successive self-nucleation and annealing and by X-ray diffraction. The copolymers are synthesized via recently invented reaction of polymer cross-metathesis, as a result of interchain exchange between polynorbornene and polyoctenamer in the presence of Grubbs’ catalyst of the first generation. This catalyst raises the fraction of trans-octenylene units up to more than 80% promoting formation of triclinic crystals. The copolymer degree of crystallinity and melting peak temperature decrease with the cross-metathesis conversion. At the same time the equilibrium melting temperature predicted by the Flory theory of copolymer crystallization is not much affected by the interchange reaction. Compared with the pure polyoctenamer or its equimolar blend with polynorbornene, the norborene-cyclooctene copolymers form considerably smaller crystallites. Thermal fractionation makes it possible to find their size distribution, which correlates with the average length of trans-octenylene blocks. Short annealing the multiblock copolymers above their melting points gives rise to a small but persistent endotherm 5–10 degrees above the annealing temperature, which is absent in polyoctenamer and, therefore, may indicate mixing of segregated norbornene and cyclooctene blocks.

Cross-metathesis of 5-hydroxycyclooctene and norbornene homopolymers affords the multiblock copolymer possessing a broad range in the degree of blockiness (from 0.03 to 1).

Heterochain polycarbosilanes are well-known materials possessed important properties. Some of their applications, such as gas separation membranes, require polymers with high molecular weight that provide good film-forming and mechanical properties. In this research, the synthesis of poly(1,1-dimethyl-1-silapentene) via the ring-opening metathesis polymerization (ROMP) of 1,1-dimethyl-1-silacyclopentene and the acyclic dienes metathesis (ADMET) of diallyldimethylsilane mediated by Ru-carbene Grubbs complexes 1st - 3rd generations as well as Hoveyda-Grubbs 2nd generation catalyst were studied for the first time. High molecular weight poly(1,1-dimethyl-1-silapentene) was synthesized by ROMP of 1,1-dimethyl-1-silacyclopentene. Varying the type and loading catalyst, temperature and monomer concentration, we obtained poly(1,1-dimethyl-1-silapentene) with Mw = 100–143 kDa, which is significantly higher (5–7 times) than that reached previously by olefin metathesis polymerization. The activities of 1,1-dimethyl-1-silacyclopentene and cyclopentene in ROMP were compared using 1H NMR monitoring the conversion of their double bonds. The ADMET polymerization of diallyldimethylsilane led to oligomers with the average polymerization degree not exceeded 4.4.

The cross-metathesis of polynorbornene and polyoctenamer in d-chloroform mediated by the 1st generation Grubbs’ catalyst Cl2(PCy3)2Ru=CHPh is studied by monitoring the kinetics of carbene transformation and evolution of the dyad composition of polymer chains with in situ 1H and ex situ 13C NMR spectroscopy. The results are interpreted in terms of a simple kinetic two-stage model. At the first stage of the reaction all Ru-benzylidene carbenes are transformed into Ru-polyoctenamers within an hour, while the polymer molar mass is considerably decreased. The second stage actually including interpolymeric reactions proceeds much slower and takes one day or more to achieve a random copolymer of norbornene and cyclooctene. Its rate is limited by the interaction of polyoctenamer-bound carbenes with polynorbornene units, which is hampered, presumably due to steric reasons. Polynorbornene-bound carbenes are detected in very low concentrations throughout the whole process thus indicating their higher reactivity, as compared with the polyoctenamer-bound ones. Macroscopic homogeneity of the reacting media is proved by dynamic light scattering from solutions containing the polymer mixture and its components. In general, the studied process can be considered as a new way to unsaturated multiblock statistical copolymers. Their structure can be controlled by the amount of catalyst, mixture composition, and reaction time. It is remarkable that this goal can be achieved with a catalyst that is not suitable for ring-opening metathesis copolymerization of norbornene and cis-cyclooctene because of their substantially different monomer reactivities.

Copolymers of norbornene and cyclooctene were synthesized for the first time by the cross-metathesis of polynorbornene with polyoctenamer. This strategy made it possible to use the 1st generation Grubbs catalyst, which exhibits low activity toward copolymerization of those monomers. Statistical multiblock copolymers with average block lengths varying from 200 to 2 units were obtained.

Silyl substituted norbornenes and their derivatives are effective monomers in the synthesis of new prospective polymer materials for gas separation membranes by metathesis and addition polymerization. Comparative activity of norbornenes (NB), norbornadienes (NBD) and tricyclononenes (TCN) with different spatial arrangement of one or two Me3Si substituents in ring-opening metathesis polymerization (ROMP) in the presence of Grubbs initiator Cl2(PCy3)2Ru =CHPh were studied by NMR and GC. It was shown that the rate of the initiation was lower than the propagation for all monomers and the highest activity was inherent to the exo-5-trimethylsilylnorbornene (5-NBSi) and 3-trimethylsilyltricyclononene (3-TCNSi). Disubstituted TCN turned out to be more active than NB having the same number and position of the substituents. The latter were more active than the corresponding NBD. It was found that syn- and anti-isomers of 3-TCNSi polymerized with close rates in contrast to exo- and endo-substituted 5-NBSi, for which polymerization rates were substantially different. Special behavior of monomers with bulky substituents in the geminal position was observed: 5,5-NBSi2 was inactive in the presence of the 1st generation Grubbs initiator, whereas it was polymerized in the presence of the 2nd generation one. Quantum-chemical calculations were in agreement with experimental data and evidenced the influence of energy, electronic and structural properties of the norbornene-type monomers studied on their activity in ROMP.

Polymers of different classes are considered as membrane materials for separation of hydrocarbons C1–C4. It has been known for a long time that solubility controlled permeation is characteristic of rubbery polymers and in particular of the most permeable rubber polydimethylsiloxane. The transport properties of these polymers are considered. Discovery of poly(trimethylsilyl propyne) and other polyacetylenes showed that similar properties can be revealed in glassy polymers. As is discussed in this review, the most important properties are reduction of the permeability of light components (CH4) in the presence of more condensable penetrant (C4H10) and higher selectivity of mixture separation as compared with ideal separation factors measured in the experiments with pure gases. Recently, two other classes of glassy polymers with solubility controlled permeation were discovered: addition type Si-containing norbornene polymers and metathesis polynorbornenes with flexible Si–O bonds in side groups. The transport properties of these novel polymers are considered in detail. It was shown that for the former group of norbornene polymers the reasons for solubility controlled permeation is great and opened porosity just as is the case for polyacetylenes. For the latter group, the presence of flexible Si–O bonds in side groups is responsible for their transport properties.

Polymers of a new class of glassy materials that demonstrate unusual solubility controlled permeability—metathesis Si–O–Si containing polynorbornenes—are synthesized. The introduction of bulky Si(OSiMe3)3 substituents into the polynorbornene backbone is shown to provide the polymers with increased gas permeability, higher than all other known metathesis polynorbornenes. The prepared glassy polymers reveal behavior similar to that known for rubbers and, in particular, siloxanes: permeability coefficients increase for the penetrants of larger size. That is, these polymers are capable to remove higher hydrocarbons from natural and associated petroleum gases.

One of the most important areas of current research is the study of the influence of the prehistory of samples of amorphous glassypolymersontheirphysicalandchemicalproperties.ThestudyofstructuralchangesbyhightemperatureIRspectroscopy compared with of quantum chemical calculations allows for an understanding of the mechanism and nature of such processes. The changes in the structure of the polymer chain depending on the type of solvent used in the formation of the films are demonstrated using the examples of several different classes of polymers. In turn, the impact of such changes in the structure on the physical and chemical properties of the polymer films is demonstrated. c � 2013 Society of Chemical Industry

Addition and metathesis copolymerization of 5-(trimethylsilyl)norbornene (TMSNB) and 5-ethylidene-2-norbornene (ENB) has been studied. High-molecular-weight metathesis copolymers have been obtained on the first-generation Grubbs catalyst based on the Ru carbene complex Cl2Ru(=CHPh)(PCy3)2 with nearly quantitative yields. Addition copolymerization has been carried out on the Ni(II) naphthenatemethylaluminoxane (MAO) catalytic system. In both cases copolymerization proceeded without participation of ethylidene double bond. Copolymers of this type are promising ones for manufacturing stable highly permeable polymeric membranes, since they are capable for crosslinking.

N and its derivatives can be polymerized, producing high molecular weight products of entirely different structure of the main chain depending on the choice of the catalysts. In the presence of the catalysts such as WCl6, RuCl3, Re2O7/Al2O3, or Grubbs Ru carbene complexes, ring-opening metathesis polymerization (ROMP) proceeds leading to formation of cyclolinear unsaturated polymers. On the other hand, norbornenes can be also polymerized via opening of double bonds like vinyl monomers in the presence of Ni and Pd catalysts. This addition-type polymerization leads to bulky bicyclic repeat units that do not contain unsaturated bonds. Most of the ROMP polynorbornenes are glassy polymers (Tg in the range ca. 40 100 C) with relatively small gas permeability (P(O2) = 1 100 barrer). However, introduction of silicon-containing substituents in monomer units significantly increases this parameter. Addition-type polynorbornenes have rigid main chains, their glass transition temperatures in most cases are above the onset of thermal decomposition (>400 C), and those that contain bulky Me3Si groups are characterized by much higher gas permeability (P(O2) = 90

The transport parameters (permeability coefficients, separation factors) were determined for the separation of mixtures of n-butane and methane. The content of butane in the feed was in the range 3.7–7.9% and simulated the composition of associated petroleum gas. The experiments were carried out at room temperature and feed pressure of 2–6 atm. Novel membrane materials – poly(trimethylsilylnorbornene) and poly(bis-(trimethylsilyl)tricyclononene) – were studied in the form of dense films. Both polymers reveal a distinct solubility controlled permeation: the permeate streams were strongly enriched (up to 58%) with the heavier component (C4H10), the permeability of methane was reduced by a factor 3–4 as compared to the permeability of pure methane, and high permeability of butane was observed. Novel Si-containing poly(cycloolefins) as membrane materials were compared with high permeability polyacetylenes.

As shown by hydrodynamic, electrooptical, and computer-simulation studies, film-forming addition silicon-substituted polynorbornene and silicon-substituted poly(1-trimethylsilyl-1-propyne), which have close gas-permeability parameters, possess similar conformational properties of chains. The molecules of the these polymers are characterized by a heterogeneous microstructure due to energetically favorable spiralization of regular sequences of monomer units with the interrelated linear sizes of helical fragments and the equilibrium rigidity of chains. Despite different chemical structures, both polymers have the statistical Kuhn segment A = (44–47) × 10−10 m and a much smaller ((10–15) × 10−10 m) kinetic fragment freely orienting under application of an electric field. The hydrodynamic and electrooptical properties of silicon-substituted polynorbornenes synthesized from the same monomer (5-trimethylsilyl-2-norbornene) via addition and metathesis mechanisms are compared. It is found that there is a significant difference in the conformational characteristics of addition and metathesis analogs. This finding gives insight into the earlier observed difference in the properties of films based on these polymers.

An approach to the manufacture of highly permeable polymers based on the synthesis and polymerization of norbornenes, norbornadienes, and tricyclononenes with different numbers and different positions of silicon-containing substituents has been developed. It has been found that these monomers are readily involved in metathesis polymerization yielding high-molecular-mass polymers possessing good filmforming properties. The addition (vinyl) polymerization of norbornenes is a more complex process; however, the product silylated polynorbornenes exhibit a higher gas permeability than the corresponding metathesis polynorbornenes. By the level of the gas-transport parameters, the silylated addition polynorbornenes obtained in the study are grouped with the most advanced high-permeability polymers. It has been shown that the presence of Me3Si substituent groups, their amount, and the main-chain structure are responsible for the enhancement of the gas permeability of polynorbornenes. Thus, a series of polymers with a regularly changing structure has been obtained, a result that makes it possible to reveal the polymer structure-property relations.

Addition polymerization of two tricyclononene monomers bearing one and two Si(CH3)3 groups was performed in the presence of Pd-containing catalysts. The polymers were obtained with high yields and were completely saturated. Good mechanical and film forming properties are observed for the polymers prepared in the presence of Pd(OAc)2/B(C6F5)3 catalyst. Their glass transition temperature was not observed until the onset of thermal decomposition (>370 °C) and the molecular weights are high (Mw up to 7 × 105). Study of gas permeation parameters of the obtained poly[3-(trimethylsilyl)tricyclononene-7] and poly[3,4- bis(trimethylsilyl)tricyclononene-7] showed that both glassy polymers revealed substantially high gas permeability. Other transport characteristics (increase in permeability in the series C1−C4 alkanes and negative activation energies of permeation) indicate that these polymers reveal so-called solubility controlled permeation, which is typical for some extra-high permeability polymers. Positron ann...

The metathesis polymerization of 5,5-bis(trimethylsilyl)norbornene, 2,3-bis(trimethylsilyl)norbornadiene, and exo,endo-3,4-bis(trimethylsilyl)tricyclo[4.2.1.02,5]non-7-ene with the catalysts WCl6/1,1,3,3-tetramethyl-1,3-disilacyclobutane, RuCl3/EtOH, and the Grubbs Ru-carbene complex Cl2(PCy3)2Ru=CHPh has been studied. New polymers with yields of up to 98% and M w = (2−39) × 105 are prepared. New metathesis copolymers of 5-trimethylsilylnorbonene with 5-(hydroxymethyl)norbornene and 5-(trimethylsiloxymethyl)norbornene are synthesized in the presence of the Cl2(PCy3)2Ru=CHPh catalyst with yields of 78 and 98%. The gas-permeability study of the above series of the metathesis polymers containing one or two Me3Si substituents in each monomer unit shows that the introduction of the second SiMe3 group markedly improves their transport characteristics. A change in the character of the backbone (polynorbornadiene, polytricyclononene) has a small effect on the permeability of the polymers. The metathesis polynorbornene with two vicinal SiMe3 groups exhibits higher gas-permeability coefficients than its isomer with germinal substituents. The homopolymer of 5-trimethylsilylnorbornene is characterized by better transport parameters than its copolymers with -OSiMe3 and -OH substituents.

Transformations of 2-trimethylsilylnorbornadiene-2,5 (SNBD) and 2,3-bis(trimethylsilyl)norbornadiene-2,5 (DSNBD) under metathesis and addition polymerization conditions were studied. In the presence of the WCl6/1,1,3,3-tetramethyldisilacyclobutane-1,3 and Cl2(PCy3)2Ru=CHPh catalysts, high-molecular-mass silicon-substituted poly(cyclopentylidene vinylene)s were obtained with yields up to 98%. Under addition polymerization conditions, SNBD and DSNBD dimerized on the nickel(II) naphthenate-methyl alumoxane catalyst to give pentacyclic dimers. Three dimers were detected in the case of SNBD, whereas the exo-trans-exo-cyclodimer alone was exclusively produced from DSNBD. Being inactive in addition homopolymerization, both SNBD and DSBND take part in addition copolymerization with norbornene.

Addition polymerization and copolymerization of bis(Me3Si)-substituted norbornene-type monomers such as 5,5-bis(trimethylsilyl)norbornene-2, 2,3-bis(trimethylsilyl)norbornadiene-2,5 and 3,4-bis(trimethylsilyl)tricyclo[4.2.1.02,5]nonene-7, in the presence of Ni(II) naphtenate/MAO catalyst were studied. Disubstituted norbornene and norbornadiene were found to be practically inactive in homopolymerization. On the other hand, their copolymerization with norbornene proceeded with moderate yields of copolymers containing predominantly norbornene units. Under studied reaction conditions 2,3-bis(trimethylsilyl)norbornadiene-2,5 was transformed into the only exo-trans-exo-dimer as a result of the [2+2]-cyclodimerization reaction. Moving Me3Si-substituents one carbon atom away from norbornene double bond made 3,4-bis(trimethylsilyl)tricyclo[4.2.1.02,5]nonene-7 active in homopolymerization and allowed to obtain addition homo-polymer with two Me3Si-substituents in each elementary unit. The reaction mechanism and steric effect of Me3Si-substituents are also discussed.

The hydrodynamic and conformational properties of silicon-containing polynorbornene prepared by metathesis polymerization of 5-trimethylsilylnorbornene in the presence of Grubbs Ru carbene complex were studied by viscometry, isothermal translation diffusion, and centrifugal sedimentation. For the ten-sample homologous series of the polymer, Mark-Kuhn-Houwink relationships correlating the hydrodynamic characteristics of the molecules in toluene with their molecular weight were obtained.

Seven polynorbornene samples containing trimethylsilyl side groups that were prepared by the addition polymerization of 5-trimethylsilyl-2-norbornene in the presence of catalytic systems (π-C5H9NiCl)2-methylaluminoxane and nickel naphthenate-methylaluminoxane have been studied by translational isothermal diffusion and viscometry. The molecular masses of the polymer samples are measured. Kuhn-Mark-Houwink equations for diffusion coefficient D and intrinsic viscosity [η] are determined in toluene at 25°C: D = 6.94 × 10−4M−0.61 and [η] = 1.53 × 10−3M0.82. The equilibrium rigidity of polymers chains is estimated as A = 47 ± 9 A. The conformational features of the silicon-containing polynorbornene are analyzed by the PM3 quantumchemical semiempirical method on the basis of simulation of its decamer chain fragments. In terms of microstructure and equilibrium rigidity, the above-described addition poly(trimethylsilylnorbornene) is close to poly(trimethylsilylpropyne) synthesized using niobium pentachloride as a catalyst. This finding explains similar membrane gas-separation properties of these polymers.

Polymerization of norbornene bearing Si(CH 3 ) 3 groups in the five position with the opening of double bonds was performed. By accurate selection of the ratios catalyst/co-catalyst and monomer/catalyst the samples with increased molecular mass (about 400,000) were obtained. Transport parameters of this, addition type poly(trimethylsilyl norbornene) (PTMSN) were measured using the gas chromatographic and mass spectrometric methods for different gases (H 2 , He, O 2 , N 2 , CO 2 , CH 4 , C 2 H 6 , C 3 H 8 and n -C 4 H 10 ). Temperature dependence of the permeability coefficients ( P ) indicated that low activation energies of permeation ( E P ) and diffusion ( E D ) are characteristic for PTMSN. In some cases (CO 2 , C 2 H 6 ) negative E P values were observed. Thermodynamics of vapor sorption in this polymer was studied using the inverse gas chromatography method. It was shown that PTMSN is characterized by very large solubility coefficients S similar to those of poly(trimethylsilyl propyne) (PTMSP). The comparison of the P , D , and S values of these highly permeable polymers showed that the greater permeability of PTMSP is determined by the larger D values. Application of different approaches for the determination of the size of microcavities in PTMSN indicated that this polymer is characterized by large size of microcavity (800–1200 Ǻ 3 ).

5,5-Bis(trimethylsilyl)norbornene-2 was synthesized in a yield of 60% via the scheme of diene condensation of cyclopentadiene with 1,1-bis(trimethylsilyl)ethylene and subsequent methylation of the resulting adduct with methyllithium. Its metathesis polymerization was first performed on W and Ru catalysts with yields of up to 98%. The structure of the new polymer was determined by means of the NMR and IR techniques. The tungsten catalyst makes it possible to prepare the polymer with a 40% amount of trans-double bonds, whereas the ruthenium catalyst is more selective and yields the polymer that contains almost 100% trans-double bonds. A high glass transition temperature as compared to other silicon-substituted metathesis polynorbornenes (196–203°C) indicates a high rigidity of the polymer chain and suggests that the polymer will have good gas-separation properties.

Polymerization of norbornene bearing Si(CH3)3 groups in the 5-position with the opening of double bonds and its copolymerization with 5-(n-hexyl)norbornene were realized in the presence of nickel(II) naphthenate/methylaluminoxane catalyst system. The completely saturated homopolymer containing Si(CH3)3 group (APNSi) and a copolymer containing both Si(CH3)3 and n-hexyl side groups (ACPNHSi) were prepared. The polymers have molecular mass of about 300 000 and a high glass transition temperature (Tg > 340 °C). Gas permeation properties of the polymers obtained were studied. APNSi reveals unusually high gas permeation parameters, e.g., P(O2) of about 800 Barrer for different samples. This polymer also exhibits solubility controlled gas permeation: the permeability coefficients increase in the series of n-alkanes C1−C4 when the size of the penetrant increases. Free volume in addition type substituted polynorbornenes was studied using positron annihilation lifetime spectroscopy (PALS). This method indicated th...

Addition polymerization of 5-trimethylsilyl- and endo -, exo -5,6-bis(trimethylsilyl)-norbornenes was studied in the presence of Ni-based catalytic systems: [π-C 5 H 9 NiCl) 2 ]-Et 3 Al 2 Cl 3 , Ni(II) naphtenate-methylaluminoxane (MAO) and (π-C 5 H 9 NiCl) 2 -MAO. Completely saturated and soluble in aromatic solvents poly(5-trimethylsilyl-2-norbornene) was obtained with the yields up to 80%. In the course of the reaction exo -conformer was consumed much faster than endo -form independently of the type of catalytic system employed. Exo -, endo -5,6-bis(trimethylsilyl)-2-norbornene was practically inactive in the presence of the studied Ni-catalysts. At the same time its addition copolymerization with norbornene and 5- n -hexyl-2-norbornene could be readily realized.

Thermodynamics of sorption of n-alkanes C4–C11 in poly(5,6-bis(trimethylsilyl)norbornene) was studied using the Inverse Gas Chromatography (IGC). Temperature dependences of the specific retention volume Vg and solubility coefficient S of various alkanes were obtained in the range 60–140 °C. For solubility coefficients, the following equation holds: ln S = 3.44 ( T c / T ) 2 − 3.90 , where Tc is the critical temperature of solutes, T is the experimental temperature and S is expressed in cm3(STP)/cm3 atm. The partial molar enthalpies ΔHm and entropies ΔSm of mixing of different n-alkanes in this glassy polymer vary in much wider range than in rubbers and display positive correlations: for more exothermic mixing process the larger negative ΔSm values are observed. It was shown that the ΔHm in poly(5,6-bis(trimethylsilyl)norbornene) pass through a minimum, when the size of solutes increases. The coordinates of ΔHm at minimum versus solute size provide an estimate of the size of free volume elements in this polymer. This conclusion was supported by variation of permeability in different glassy polymers studied using IGC and by the results of other methods for probing free volume in glassy polymers.

Using ring opening metathesis polymerization (ROMP) the novel linear polynorbornadiene and polynorbornene (PNB) derivatives bearing silicon-containing moieties were prepared in the presence of RuCl 3 ·3H 2 O, RuCl 2 (PPh 3 ) 3 , and WCl 6 /tetramethyldisilacyclobutane catalysts with the yields up to 98%. Gas permeation properties (permeability and diffusion coefficients) of the polymers obtained were measured. It was shown that polynorbornadiene containing the Si(CH 3 ) 3 group has the transport parameters similar to those of poly(trimethylsilyl norbornene) studied earlier. On the other hand, PNB bearing two Si(CH 3 ) 3 groups in each repeat unit reveals much greater gas permeability induced mainly by increased solubility coefficients. The latter result is consistent with the much higher glass transition temperature of this polymer.

A new series of tricyclononene derivatives with two and three silyl groups are successfully synthesized via [2σ+2σ+2π]-cycloaddition of silylethylenes to quadricyclane. The activity of the silylethylenes in the cycloaddition reactions was estimated.