Synthesis and Gas-Transport Properties of Metathesis Polytricyclononenes Bearing Three Me₃ Si Groups per Monomer Unit

Abstract

A new metathesis polynorbornene containing three SiMe3 groups per monomer unit directly connected to the norbornene moiety via SiC bonds is synthesized. The ring‐opening metathesis polymerization of sterically hindered 3,3,4‐tris(trimethylsilyl)tricyclononene‐7 is successfully conducted in yields 80–85% in the presence of first generation Grubbs catalyst. The corresponding polymer is obtained with molecular weight Mw up to 5.4 × 105 Da. It is an amorphous glassy (Tg = 200 °C) polymer with high thermal stability. Gas permeability and diffusivity coefficients are studied for a range of gases (He, H2, O2, N2, CO2, CH4). This polymer containing three SiMe3 groups per monomer unit turns out to be more permeable (P(O2) = 125 Barrer) than similar polymers with one or two SiMe3 groups per monomer unit (P(O2) = 30–50 Barrer). Wide angle X‐ray diffraction, positron annihilating lifetime spectroscopy, as well as Brunauer–Emmett–Teller investigations are also performed and discussed.

Synthesis and Gas‐Transport Properties of Novel Copolymers Based on Tricyclononenes Containing One and Three Me3Si‐Groups

“…Previously we have shown that the introduction of three SiMe 3 ‐groups directly attached to the norbornene structure (i.e., 3,3,4‐tris(trimethylsilyl)tricyclononene‐7) dramatically lowered monomer activity in metathesis polymerization in comparison with monomers containing only one or two SiMe 3 ‐groups . At the same time we observed a significant increase in gas permeability of the corresponding metathesis polymer having three SiMe 3 ‐groups per a monomer unit.…”

Addition Homo‐ and Copolymerizations of Dicyclopentadiene and 5‐n‐Hexylnorbornene in the Presence of Pd‐N‐Heterocyclic Carbene Complexes

“…Brunauer, Emmett, and Teller (BET) surface area of this polymer was 155 m 2 g −1 and total pore volume was 0.176 cm 3 g −1 (the mesopore volume was 0.075 cm 3 g −1 ). Although these values are not high and lower than similar characteristics for earlier studied addition polynorbornenes with side bulky Me 3 Si‐groups, they are much higher than for different metathesis polymers with bulky substituents or addition homopolymer from HexNB (BET surface area < 1 m 2 g −1 ). Mesopore and micropore size distributions were estimated using BJH and Horvath–Kawazoe methods accordingly ( Figure ).…”

“…The maximum mass increment was about 12%. This is in contrast to metathesis polynorbornenes containing internal double bonds in main chains: for them the increase of mass was not found in TGA curves in air . The oxidation of double bonds in poly(DCPD) was also observed at room temperature for polymer samples stored in air that was confirmed by IR spectroscopy (Figure S3, Supporting Information) and elemental analysis.…”

Macromolecular Design and Synthesis of Polymers from Silicon- Containing Norbornenes for Membrane Gas Separation

“…The polynorbornenes and polytricyclononenes bearing three Me 3 Si-groups per one monomer unit were found to be more permeable than their counterparts with two Me 3 Si-substituents in the same unit (Figs. 6, 7) [59,69,71,86]. An increase in the gas permeability composed 20-300% and depended on the binding patterns of Me 3 Si-substituents with the main chains.…”

“…The first one is based on the introduction of bulky and rigid silicon-containing substituents (i.e., Me 3 Sigroups) into the monomer units of polynorbornenes. As a rule, the gas permeability coefficients essentially grow with an increase in the number of these groups per a monomer unit [24,[69][70][71][72]. Another way to improve the permeability characteristics of polynorbornenes is the synthesis of polymers with rigid main chains.…”