Microporous Thioxanthone Polymers as Heterogeneous Photoinitiators for Visible Light Induced Free Radical and Cationic Polymerizations

Conjugated microporous polymeric networks possessing thioxanthone groups were reported to initiate free radical and cationic polymerizations of vinyl monomers and cyclic ethers, respectively, under visible light irradiation. These new classes of <i>Type II</i> macrophotoinitiators with high porosity having large BET surface area of 500–750 m² g^–1 were prepared through different cross-coupling processes. Polymerizations are successfully achieved in conjugation with several co-initiators benefiting from hydrogen abstraction or electron transfer reactions stimulated by either visible light or natural sunlight irradiation. Photopolymerizations conducted by using knitted photoinitiators show better conversion and rate of polymerization than those obtained via Sonogashira–Hagihara coupling. The heterogeneous nature of the photoinitiators makes them easily separable from the media and more importantly reusable for further polymerizations while retaining the photocatalytic activity

Impact of Water Coadsorption for Carbon Dioxide Capture in Microporous Polymer Sorbents

Alcohol-containing polymer networks synthesized by Friedel–Crafts alkylation have surface areas of up to 1015 m²/g. Both racemic and chiral microporous binaphthol (BINOL) networks can be produced by a simple, one-step route. The BINOL networks show higher CO₂ capture capacities than their naphthol counterparts under idealized, dry conditions. In the presence of water vapor, however, these BINOL networks adsorb less CO₂ than more hydrophobic analogues, suggesting that idealized measurements may give a poor indication of performance under more realistic carbon capture conditions

Swellable, Water- and Acid-Tolerant Polymer Sponges for Chemoselective Carbon Dioxide Capture

To impact carbon emissions, new materials for carbon capture must be inexpensive, robust, and able to adsorb CO₂ specifically from a mixture of other gases. In particular, materials must be tolerant to the water vapor and to the acidic impurities that are present in gas streams produced by using fossil fuels to generate electricity. We show that a porous organic polymer has excellent CO₂ capacity and high CO₂ selectivity under conditions relevant to precombustion CO₂ capture. Unlike polar adsorbents, such as zeolite 13x and the metal–organic framework, HKUST-1, the CO₂ adsorption capacity for the hydrophobic polymer is hardly affected by the adsorption of water vapor. The polymer is even stable to boiling in concentrated acid for extended periods, a property that is matched by few microporous adsorbents. The polymer adsorbs CO₂ in a different way from rigid materials by physical swelling, much as a sponge adsorbs water. This gives rise to a higher CO₂ capacities and much better CO₂ selectivity than for other water-tolerant, nonswellable frameworks, such as activated carbon and ZIF-8. The polymer has superior function as a selective gas adsorbent, even though its constituent monomers are very simple organic feedstocks, as would be required for materials preparation on the large industrial scales required for carbon capture