Polymerization of diphenylacetylenes having very bulky silyl groups and polymer properties

Abstract

Polymerization and polymer properties of 1‐phenyl‐2‐[4‐(triphenylsilyl)phenyl]acetylene (pPh3SiDPA) and 1‐phenyl‐2‐[4‐(triisopropylsilyl)phenyl]acetylene (piPr3SiDPA), which have very bulky silyl groups, were examined. These monomers polymerized in good yields in the presence of TaCl5‐based catalysts. The highest weight‐average molecular weights of poly(pPh3SiDPA) and poly(piPr3SiDPA) reached about 1 × 106 and 4.8 × 106, respectively. The polymers were yellow to orange‐colored solids which were soluble in toluene, chloroform, etc., and provided free‐standing films by solution casting. The onset temperatures of weight loss of poly(pPh3SiDPA) and poly(piPr3SiDPA) in TGA in air were 430 and 270°C, respectively. The oxygen permeability coefficients of poly(pPh3SiDPA) and poly(piPr3SiDPA) at 25°C were 3.8 and 20 barrers, respectively, and relatively small. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2721–2725, 1998

Highly Gas-Permeable Silanol-Functionalized Poly(diphenylacetylene)s: Synthesis, Characterization, and Gas Permeation Property

“…The P values of 2b were about twice as large as those of 2a . The permeability coefficients of phenoxysilyl group-containing poly(diphenylacetylene)s are comparable to bulky silyl group-containing poly(diphenylacetylene)s reported previously. − The D (CO 2 ) value of 2b was 2.8 times larger than that of 2a , while the FFVs of 2a and 2b were nearly the same value. FFV value is one of important factors for permeability of membrane, but local mobility of substituents also affects gas permeability.…”

Modified polysulfones. IV. Synthesis and characterization of polymers with silicon substituents for a comparative study of gas‐transport properties

“…The introduction of other sterically more bulky silyl side groups led to a large decrease in oxygen permeability, but with an increase in oxygen/nitrogen permselectivity 13. A similar trend was observed in polydiphenylacetylenes with very bulky triphenylsilyl groups, where the decrease in permeability from trimethylsilyl was more than 2 orders of magnitude 15. Polydimethylsiloxane is a rubbery polymer with a silicon backbone that also has very high gas permeabilities, although of an order of magnitude less than PTMSP 16, 17.…”

Kinetic Study on Achiral-to-Chiral Transformation of Achiral Poly(diphenylacetylene)s via Thermal Annealing in Chiral Solvent: Molecular Design Guideline for Conformational Change toward Optically Dissymmetric Structures

“…The present achiral PDPAs were synthesized according to a previously reported method. , All polymerization reactions for the preparation of the PDPAs were conducted very carefully under the same conditions, e.g., temperature and time, to exclude any possible influence of the polymerization conditions on the degree of stacking between the side phenyl rings . This approach guarantees an exact comparative analysis of the annealing effect on the chiroptical properties of the polymers.…”

“…All the polymers used in this work were synthesized following a previously reported method. , All polymerization were performed under the same conditions by heating the reaction mixture at 80 °C for 1 h. All the polymers existed in the solid state at room temperature, although individual differences in brittleness were observed. The polymerization yield, weight-average molecular weight ( M w ), number-average molecular weight ( M n ), and polydispersity index (PDI) of pMe3, pEt3, p i Pr3, pPh3, pMe2O1, pMe2OD1, and mMe3 are summarized in Table S1.…”