Synthesis, Structure and Properties of Poly(1-trimethylsilyl-1-propyne) Obtained with NbBr5- and TaBr5-Based Catalytic Systems

The Supramolecular Organization and Surface Morphology of Films of Poly(1-trimethylsilyl-1-propyne) with Different Configurational Compositions

“…The presence of additional maxima is characteristic for PTMSP and is evidence of a somewhat more ordered supramolecular organization of this polymer in comparison with typically amorphous glass-like polymers. Overall, the appearance of diffraction patterns of PTMSP films is similar to earlier recorded diffraction patterns of powders [17]. However, differences from powders are observed in the diffraction patterns of films.…”

“…Our group has already developed methods for the synthesis of PTMSP with the use of catalyst systems based on Nb and Ta pentachlorides and pentabromides, which make it possible to vary the ratio of cis-/trans-units in the polymer in a wide range, from the mixed composition (the concentration of cis-units of 40-60%) to cis-regular composition (up to 100% cis-units), by polymerization conditions. PTMSPs with the concentration of cis-units >90% are not soluble in any of the organic solvents due to the highly regular microstructure and a more ordered supramolecular organization in comparison with PTMSP with a lower cis-concentration determined by it [17]. Because of this, a series of soluble samples of PTMSP with the concentration of cis-units of 40 to 80% was synthesized in this study over catalyst systems based on Nb and Ta pentachlorides and pentabromides to obtain films from solutions.…”

“…The decrease in permeability coefficients with growth in the concentration of cis-units correlates with the decrease in the cluster size and growth in the ordering of supramolecular organization. At the same time, the supramolecular organization of PTMSP, which depends on the configurational composition of macrochains, affects not only its transport characteristics but also the solubility in organic substances [13,17]. Along with transport parameters, a very important characteristic of a polymer membrane material is its resistance to components of mixtures under separation.…”

“…The permeability coefficients for PTMSP with mixed configurational compositions (40-60% cis-units) are somewhat higher than for cis-enriched PTMSP (80% cis-units). However, the higher degree of stereoregularity of cisenriched PTMSP determines its insolubility in most organic solvents due to more ordered supramolecular organization [17]. The variation of the configurational composition of PTMSP paves the way for obtaining a polymer combining the optimum characteristics for specific membrane applications.…”

“…In [14,16], the analysis of the supramolecular organization of PTMSP in the form of films by X-ray diffraction (XRD) was performed for samples synthesized over traditional catalyst systems based on Nb and Ta pentachlorides and possessing a mixed configura-tional composition (the concentration of cis-units of 40-60%). In [17], samples of PTMSP obtained using new catalyst systems based on Nb and Ta pentabromides were studied, and the configurational composition of PTMSP varied in a wider range, from mixed (60% cis-units) to cis-regular. However, in this study, the evaluation of the effect of configurational composition of PTMSP on its supramolecular organization was performed based on the analysis of diffraction patterns of the polymer in a powder.…”