Synthesis, geometric structure, and properties of poly(phenylacetylenes) with bulkypara-substituents

Abstract

Phenylacetylenes (PAs) with bulky substituents (adamantyl, tert‐butyl, and n‐butyl groups) at the para‐position polymerized in good yields with Fe, Rh, Mo, and W catalysts. The formed polymers were soluble, and their number‐average molecular weights were in the range of thousands to hundred thousands. Whereas it is known that the poly(PA) obtained with the Fe catalyst is an insoluble cis‐cisoidal polymer, the present polymers formed with the same catalyst were totally soluble in many solvents such as benzene and CHCl3. The 1H‐ and 13C‐NMR and DSC data revealed that both of the polymers formed with the Fe and Rh catalysts had virtually all‐cis structures, while those with the Mo and W catalysts had cis‐rich and trans‐rich structures, respectively. Cis‐cisoidal and cis‐transoidal structures of para‐substituted poly(PAs) could not be distinguished because of their good solubility. The bulky substituents raised the temperature of cis–trans isomerization and improved the thermal stability of the polymers. Poly(p‐t‐BuPA) showed gas permeability higher than that of poly(PA). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3157–3163, 1998

Cationic Rhodium Complexes with Hemilabile Phosphine Ligands as Polymerization Catalyst for High Molecular Weight Stereoregular Poly(phenylacetylene)

“…No thermal decomposition was observed at temperatures below 200 °C and only a slight weight lose (approximately 4%) was detected. A sharp weight lose corresponding to thermal descomposition was observed above 250 °C (onset on the decomposition step), what is in accordance with the TGA curves of other poly(phenylacetylene)s analyzed . The DSC curves for the same polymer sample are illustrated in Figure b (three consecutive heating/cooling processes at 10 °C/min were recorded).…”

SEC/DAD and1H NMR Study of Molecular Weight and Configurational Stability of Poly(2,4-difluorophenylacetylene) and Polyphenylacetylene Prepared with Rh Catalyst

“…[46][47][48][49][50][51][52][53][54] The main chains of substituted polyacetylenes consist of alternating single and double CÀC bonds that are more or less conjugated in dependence on the main-chain configuration and character of substituents. This covalent structure imparts to substituted polyacetylenes the unique properties.…”

Synthesis, properties, and gas permeability of novel poly(diarylacetylene) derivatives

“…It is noteworthy that these poly(diphenylacetylene) derivatives show much higher thermal stability compared to para-substituted poly(phenylacetylenes). 21 When 2a-g were heated in air above 800 8C, the ash composed of silica remained, whose amount agreed with the expected value in every case. In Figure 2, the desilylated polymers 3a-e showed practically identical TGA curves to one another.…”