Subnanoporous Highly Oxygen Permselective Membranes from Poly(conjugated hyperbranched macromonomer)s Synthesized by One-Pot Simultaneous Two-Mode Homopolymerization of 1,3-Bis(silyl)phenylacetylene Using a Single Rh Catalytic System: Control of Their Structures and Permselectivities

Abstract

Novel well-defined complex polymers, polymers of acetylenetype macromonomers having silylene−vinylene−phenylene−ethynylene hyperbranches, investigated as a new class of subnanoporous oxygen permselective membrane materials, were synthesized very easily by one-pot simultaneous twomode homopolymerization of a single monomer with a single catalyst. For this "simultaneous polymerization" we synthesized AB 2 -type monomers (1,3bis(dimethylsilyl)phenylacetylenes) containing one terminal triple bond and two Si−H groups. The resulting poly(hyperbranched macromonomer)s had high molecular weights, low densities, high solubility, and good self-membrane forming ability. They had higher oxygen permselectivities (α = P O 2 /P N 2 ) than any other reported polymers having similar oxygen permeabilities (P O 2 ). These excellent polymer membranes could be obtained only by the simultaneous polymerization. In the one-pot simultaneous polymerization, the two different modes of polymerizations, i.e., addition polymerization of the triple bond and polyaddition of the triple bond and two SiH groups in the single monomer, occurred simultaneously by using one catalytic system, i.e., [Rh(norbornadiene)Cl] 2 /various amines. The ratio of the branches (RB), i.e., the addition polymerization and the polyaddition, could be controlled by changing the amine cocatalysts. Their oxygen permselectivities could be adjusted by controlling the polymer structures including RB.

Synthesis of Cis-Cisoid or Cis-Transoid Poly(Phenyl-Acetylene)s Having One or Two Carbamate Groups as Oxygen Permeation Membrane Materials

“…In order to confirm the main chain conformations of the three new polymers having one or two carbamate groups (poly( 1 ), poly( 2 ), and poly( 3 )), UV-vis spectra were measured for them, together with poly( 4 ) having no carbamate groups ( Figure 3 ). Since poly( 1 ) and poly( 2 ) showed a similar UV-vis pattern to poly( 4 ), whose main chain had a very tight cis-cisoid conformation maintained by intramolecular hydrogen bonds reported by our group [ 13 , 14 ], we concluded that poly( 1 ) and poly( 2 ) took very tight cis-cisoid conformations. On the other hand, the UV-vis spectrum of poly( 3 ) showed different absorption bands from those of poly( 1 ) and poly( 2 ).…”

“…Most of poly(substituted acetylene)s reported take cis-transoid conformation. On the other hand, the poly(substituted acetylene with two hydroxyl groups)s we reported take cis-cisoid conformation [ 13 , 14 , 15 ]. As a result, they are expected to have a more rigid backbone than cis-transoid poly(substituted acetylene)s. Therefore, cis-cisoid poly(substituted acetylene)s are very promising as better oxygen permeation membrane materials if their processability is good.…”

“…In general, polymers obtained by the polymerization of monosubstituted acetylenes using a (Rh(norbornadiene)Cl) 2 (norbornadiene = nbd) catalytic system take a cis-transoidal loosely helical conformation [ 16 , 17 , 18 , 19 ]. We have been reporting poly(phenylacetylene)s taking a cis-cisoidal tightly helical conformation from monomers having two hydroxy groups, such as 4 (in Chart 1), using a similar catalytic system [ 13 , 14 ]. The cis-cisoidal tightly helical conformation of poly( 4 ) was kept by an intramolecular hydrogen bond between the OH groups [ 14 ].…”

“…We have been reporting poly(phenylacetylene)s taking a cis-cisoidal tightly helical conformation from monomers having two hydroxy groups, such as 4 (in Chart 1), using a similar catalytic system [ 13 , 14 ]. The cis-cisoidal tightly helical conformation of poly( 4 ) was kept by an intramolecular hydrogen bond between the OH groups [ 14 ]. Although the monomer is very valuable, because it is the only monomer to give such polymers, the structures of suitable monomers giving such polymers are very limited.…”

“…We have previously reported these cis-cisoid and cis-transoid conformation can be determined by UV-vis spectroscopy because the conjugation length of the former is shorter than that of the latter [ 13 , 14 , 18 , 19 ]. For the extensive consideration, see Ref.…”