Poly(vinyl trimethylsilane) and block copolymers of vinyl trimethylsilane with isoprene: Anionic polymerization, morphology and gas transport properties

Abstract

Poly(vinyl trimethylsilane) (PVTMS) and block copolymers of vinyl trimethylsilane with isoprene were synthesized by anionic polymerization and characterized. The synthesized pure PVTMS has properties similar to a reference material produced about two decades ago and can be used for thin film composite membrane formation. Even at low isoprene content the block copolymers have improved film forming properties compared to the pure PVTMS. However, the presence of the isoprene units in the block copolymers leads to a decrease of the gas permeability but does not affect the selectivity of the membranes (a(O 2 /N 2) = 3.9).

Modification of polyisoprene‐block‐poly(vinyl trimethylsilane) block copolymers via hydrosilylation and hydrogenation, and their gas transport properties

“…A TEM of Hs‐PI‐ b ‐PVTMS [Fig. (b)] block copolymer composed of 80% randomly hydrosilylated PI block ( M w = 21.6 kg mol −1 ) and PVTMS ( M w = 144.4 kg mol −1 ) is displayed in comparison with the initial PI‐ b ‐PVTMS from the previous study in Figure (a) . In this image, hydrosilylated PI‐ b ‐PVTMS block copolymer revealed no microphase separation.…”

“…The block copolymers of a liquid crystalline block and an amorphous block tend to form a lamellar structure over larger compositional ranges as compared to block copolymers composed of two amorphous blocks. In the lamellar structure, continuous layers of PI lamellae effectively blocked the permeation of gases . After hydrosilylation of the PI block, the characteristic of this block and the interactions between the blocks were changed.…”

“…PVTMS is also expensive and excessive consumption of the polymer occurs during integral asymmetric gas separation membrane fabrication. These drawbacks of PVTMS led us to the idea to synthesize block copolymers of PVTMS (hard segment) and isoprene (soft segment) and to study their gas transport and membrane formation properties . The block copolymers (PI‐ b ‐PVTMS) were found to have excellent film forming properties accompanied by the O 2 permeability and O 2 /N 2 selectivity close to pure PVTMS.…”

“…The block copolymers (PI‐ b ‐PVTMS) were found to have excellent film forming properties accompanied by the O 2 permeability and O 2 /N 2 selectivity close to pure PVTMS. However, at high isoprene content in the block copolymer, formation of a lamellar structure during microphase separation caused a 53% drop in O 2 permeability but no significant difference in O 2 /N 2 selectivity compared to PVTMS‐ref . This drawback led us to the idea to modify the isoprene units of PI‐ b ‐PVTMS chemically to improve the permeability of the rubbery block.…”

Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization

“…Fascinating microstructures for manifold applications are accessible via self-assembly of such polymers [21]. For example, well-defined BCs consisting of polyisoprene and polymers with laterally bonded alkyl-silane groups were recently prepared by sequential anionic polymerization and have been used as membranes for gas separation applications [22]. The anionic ring opening polymerization (ROP) of ring-strained cyclic silanes, carbosilanes and metal-containing carbosilanes has also been reported and lead to well-defined polymers [23][24][25][26][27][28][29][30][31][32].…”