Synthesis and characterization of a chiral copoly(ether sulfone) with high molecular weight

Abstract

A series of chiral poly(ether sulfone)s containing (S)-binaphthyl unit were synthesized via nucleophilic substitution polycondensation. The as-synthesized polymers were characterized by NMR. The molecular weights of these polymers were calculated by viscosity and gel permeation chromatography. The thermal stability was measured by TGA. The optical activities of the polymers were studied by circular dichroism and optical rotation. It was found that introducing more reactive 2,2 -biphenol monomer to partly substitute the binaphthol monomer could increase the molecular weight of the polymer from 4.1 × 10 4 to 9.8 × 10 4 g mol −1 . Meanwhile, the thermal stability increased and the decomposition temperature rose from 447 to 518 • C, with the optical activity of the polymer well preserved. However, the value of the specific optical rotation decreased with increasing biphenol to binaphthol molar ratio. In addition, the optical rotation direction of the polymer was contrary to that of the pristine binaphthol monomer, which indicated that the chiral polymers formed a secondary structure.

A Cross-Linked and Swelling Polymer as an Effective Solid Acid Catalyst

“…We also tried to prepare the catalyst without DCDPS; unfortunately, the yield was very low (below 5%), which can be assigned to oligomers with small molecular weight dissolving in water during the precipitation process. This indicated that the sulfonated monomer SDCDPS had lower reactivity than unsulfonated monomer DCDPS because of the steric effect . A small amount of DCDPS (10% molar ratio) can greatly improve the yield of polymers (>70%).…”

“…This indicated that the sulfonated monomer SDCDPS had lower reactivity than unsulfonated monomer DCDPS because of the steric effect. 45 A small amount of DCDPS (10% molar ratio) can greatly improve the yield of polymers (>70%). Unlike the linear poly(ether sulfone) catalyst which dissolved in hot water when the molar ratio of SDCDPS and DCDPS was higher than 6:4, the cross-linked poly(ether sulfone) with a much higher molar ratio of 9:1 did not dissolve in hot water, which indicated the cross-linker monomer was successfully introduced into the polymer framework.…”

Relationships between main-chain chirality and photophysical properties in chiral conjugated polymers

“…4) show only negative and newly emerged CD signals around 255, 290, and 375 nm in R-polymers, while in S-polymers only positive signals in mirror images of those of R-polymers were observed in both THF solution and lms, providing direct evidence for the successful introduction and transfer of the chirality into the conjugated polymers. This transition between monomer and polymer conrmed by both CD spectra and [a 25 D ] indicates the formation a secondary structure 41 probably due to the transfer of the chirality in the polymer backbone. Due to the high enantiomerization barrier of binaphthols, 42 they are stable enough to survive the polymerization conditions and main-chain relaxation to maintain their intrinsic chirality and induce new ones aer interactions with the other units in the conjugated backbone.…”

Recent Progress on the Synthesis of Chiral Sulfones

“…The chiral copoly(ether sulfone) polymers containing ( S )‐binaphthyl unit were expected to be used in chiral catalysis, molecular recognition and enantioselective. separation [16] …”