Poly[1‐(trimethylgermyl)‐1‐propyne] and poly[1‐(trimethylsilyl)‐1‐propyne] with various geometries: Their synthesis and properties

Abstract

The polymerization of 1,2-disubstituted acetylenes [1-(trimethylgermyl)-1propyne and 1-(trimethylsilyl)-1-propyne] initiated by Nb-and Ta-based catalytic systems was studied within a wide temperature range (Ϫ10 to ϩ80°C) with solvents (cyclohexane, CCl 4 , toluene, anisol, and n-chlorobutane) with variable dielectric constants (2.023-7.390). Conditions ensuring the synthesis of poly[1-(trimethylsilyl)-1propyne] (PTMSP) containing 20 -80% cis units and poly[1-(trimethylgermyl)-1-propyne] (PTMGP) containing 3-65% cis units were determined. The PTMSP and PTMGP samples were amorphous, exhibited a two-phase structure characterized by the presence of less ordered regions and regions with an enhanced level of ordering, and differed in solubility. A correlation was found between the cis/trans ratio and the morphology, the geometrical density of PTMSP and PTMGP films, and the gas permeability of the polymers. The gas permeability and solubility behavior of PTMSP and PTMGP were examined in terms of the molecular characteristics of the polymer samples (the thermodynamic Kuhn segment and the Kerr electrooptic effect). It was demonstrated that the gas permeability, as well as the solubility of the polymers, was defined by their supramolecular ordering, which depended on the lengths of continuous sequences composed of units of analogous microstructures and on the flexibility of macrochains.

Substituted polyacetylenes

“…IR spectroscopic study of the polymers in CHCl 3 revealed that most of the pendant carbamate groups participate in intramolecular hydrogen bonding. The chiral polymer from 19b existed in a helical conformation with an excess of one-handed screw sense, which was supported by the very large optical rotation ( 88), meaning that the intramolecular hydrogen bonds induce the helical conformation of poly (19). The contribution of the hydrogen bonds to the secondary structure was also supported by variation in the CD and UV-vis spectra of poly (19) upon the addition of methanol.…”

“…Later, more detailed study was done by another research group regarding the geometric structure of poly (11). 88 …”

Poly[1-(trimethylsilyl)-1-propyne] as a solvent resistance nanofiltration membrane material

“…[η] = 0.45 dl/g; cis/trans ratio: 63/37) was synthesized using NbCl 5 , as a catalyst, and toluene as a solvent [9]. It has been chosen due to its good stability in time [10][11][12] and stable performance in pervaporation separation of ethanol [13].…”

A Novel Poly(4‐methyl‐2‐pentyne)/TiO2 Hybrid Nanocomposite Membrane for Natural Gas Conditioning: Butane/Methane Separation

“…These changes may not be only in size but also in the distribution of freevolume elements, which depends on the polymer microstructure, and thus differences in the gas permeability of the PMP samples could be mainly attributed to polymer microstructure. [30] In order to improve the performance of the membranes made from PMP for butane/methane separation, PMP/ TiO 2 nanocomposite membranes were prepared. Hybrid organic/inorganic membranes are considered as a promising alternative to conventional polymeric membranes.…”