The Use of the Thiol-Ene Addition Click Reaction in the Chemistry of Organosilicon Compounds: An Alternative or a Supplement to the Classical Hydrosilylation?

This review presents the main achievements in the use of the thiol-ene reaction in the chemistry of silicones. Works are considered, starting from monomers and ending with materials.The main advantages and disadvantages of this reaction are demonstrated using various examples. A critical analysis of the use of this reaction is made in comparison with the hydrosilylation reaction.

Photopatterning of two stage reactive polymer networks with CO2-philic thiol–acrylate chemistry: enhanced mechanical toughness and CO2/N2 selectivity

Two stage reactive polymer (TSRP) networks can be programmed with spatially varying heterogeneity, presenting a new way of designing material structure and controlling or enhancing properties.

Tailoring Crosslinked Polyether Networks for Separation of CO2 from Light Gases

Crosslinked poly(ethylene oxide) or poly(ethylene glycol) (PEG) is an ideal membrane material for separation of CO₂ from light gases (e.g., H₂ , N₂ , O₂ , CH₄ etc). In these membranes, crosslinking is used as a tool to suppress crystallinity of the PEG segments. In spite of the extensive effort to develop crosslinked PEG membranes in the last two decades, it remains a challenge to establish the structure-property relationships. This paper points out the fundamental limitations to correlate the chain topology of a network with the gas permeation mechanism. While a quantitative comparison of the molecular weight between crosslinks of networks and gas permeation mechanism reported by different research groups is challenging, effort is made to draw a qualitative picture. In this review, a focus is also put on the progress of utilization of dangling chain fractions to tailor the gas permeation behavior of PEG networks.

Cross-Linked Polyphosphazene Blends as Robust CO2 Separation Membranes

An effective cross-linking technique allows a viscous and highly gas-permeable hydrophilic polyphosphazene to be cast as solid membrane films. By judicious blending with other polyphosphazenes to improve the mechanical properties, a membrane exhibiting the highest CO₂ permeability (610 barrer) among polyphosphazenes combined with a good CO₂/N₂ selectivity (35) was synthesized and described here. The material demonstrates performance stability after 500 h of exposure to a coal-fired power plant flue gas, making it attractive for use in carbon capture applications. Its CO₂/N₂ selectivity under conditions up to full humidity is also stable, and although the gas permeability does decline, the performance is fully recovered upon drying. The high molecular weight of these heteropolymers also allows them to be cast as a thin selective layer on an asymmetric porous membrane, yielding a CO₂ permeance of 1200 GPU and a CO₂/N₂ pure gas selectivity of 31, which does not decline over 2000 h. In addition to gas separation membranes, this cross-linked polyphosphazene can potentially be extended to other applications, such as drug delivery or proton exchange membranes, which take advantage of the polyphosphazene's versatile chemistry.

Probe Into the Influence of Crosslinking on CO2 Permeation of Membranes

Crosslinking is an effective way to fabricate high-selective CO₂ separation membranes because of its unique crosslinking framework. Thus, it is essentially significant to study the influence of crosslinking degree on the permeation selectivities of CO₂. Herein, we report a successful and facile synthesis of a series of polyethylene oxide (PEO)-based diblock copolymers (BCP) incorporated with an unique UV-crosslinkable chalcone unit using Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT) process. The membranes of as-prepared BCPs show superior carbon dioxide (CO₂) separation properties as compared to nitrogen (N₂) after UV-crosslinking. Importantly, the influence of different proportions of crosslinked chalcone on CO₂ selectivities was systematically investigated, which revealed that CO₂ selectivities increased obviously with the enhancement of chalcone fractions within a certain limit. Further, the CO₂ selectivities of block copolymer with the best block proportion was studied by varying the crosslinking time which confirmed that the high crosslinking degree exhibited a better CO₂/N₂ (α_CO2/N2) selectivities. A possible mechanism model revealing that the crosslinking degree played a key role in the gas separation process was also proposed.

Water dispersible siloxane nanogels: a novel technique to control surface characteristics and drug release kinetics

Amphiphilic, water-dispersible, crosslinked siloxane nanogels were synthesized and applied as optically clear, functional coatings on the surface of lens substrates to demonstrate the feasibility of siloxane-nanogels to generate covalently tethered coatings and modify the surface properties of intraocular lens substrates.

Separation of carbon dioxide from flue gas by mixed matrix membranes using dual phase microporous polymeric constituents

Microporous polymeric mixed matrix membranes for CO₂ separation from actual flue gas of a coal-fired power plant.