Effects of Poly(glycidyl ether) Structure and Ether Oxygen Placement on CO₂ Solubility

Abstract

The solubility of CO 2 in poly(ethylene oxide), poly(ethyl glycidyl ether), poly(iso-propyl glycidyl ether), poly(allyl glycidyl ether), poly(n-butyl glycidyl ether), and poly(ethyl vinyl ether) was measured at room temperature and 333.15 K and pressures up to 15 bar. CO 2 solubility, expressed as mole fraction in terms of molecular weight of the polymer repeat unit, was directly related to polymer repeat unit molecular weight regardless of pendant chain structure or ether oxygen placement in the backbone. The molality of CO 2 was highest in poly(ethyl vinyl ether) and was equal in all the poly(glycidyl ethers) and poly(ethylene oxide). The standard enthalpies and entropies of CO 2 absorption in poly(ethylene oxide), poly(ethyl glycidyl ether), and poly(ethyl vinyl ether) were calculated from the Henry's constants obtained from three isotherms. CO 2 dissolution was slightly more favorable enthalpically in poly(ethylene oxide). However, the entropic penalty for absorption was lower in poly(ethyl glycidyl ether) and poly(ethyl vinyl ether). These results suggest that poly(glycidyl ethers) and poly(ethyl vinyl ether) are promising alternatives to poly(ethylene oxide) for CO 2 separation by absorption or membrane separation because they have similar CO 2 uptake capacity, low glass transition temperatures, are amorphous, and are more hydrophobic than poly(ethylene oxide).

Polyethers Based on Short-Chain Alkyl Glycidyl Ethers: Thermoresponsive and Highly Biocompatible Materials

“…In recent work, Brennecke, Lynd, and co-workers synthesized PEGE and P i PGE ( M n = 5.1 and 7.0 kg mol –1 , respectively) by AROP, albeit with higher dispersities (1.98 for PEGE). The respective polymers were further investigated regarding their interaction in binary blends with ionic liquids as well as their capability to solubilize CO 2 . , …”

“…The authors therefore suggest that poly­(glycidyl ethers) are promising alternatives to PEG. The highly useful properties regarding CO 2 separation are preserved, while the limiting semicrystallinity of PEG is avoided by utilization of amorphous poly­(glycidyl ethers), rendering also higher molecular weights usable …”

“…The respective polymers were further investigated regarding their interaction in binary blends with ionic liquids as well as their capability to solubilize CO 2 . 54,55 In addition to low-molecular-weight alkoxide initiators, PEG is also a suitable macroinitiator for AROP of SCAGEs due to its primary hydroxy termini. Different research groups reported the synthesis of ABA triblock copolymers via polymerization of iPGE as well as the copolymerization of EGE and iPGE initiated by PEG, affording PiPGE-b-PEG-b-PiPGE 56 and P(EGE-co-iPGE)-b-PEG-b-P(EGE-co-iPGE), 57−59 respectively (Figure 4).…”

“…The highly useful properties regarding CO 2 separation are preserved, while the limiting semicrystallinity of PEG is avoided by utilization of amorphous poly(glycidyl ethers), rendering also higher molecular weights usable. 55 ■ CONCLUSION AND OUTLOOK Poly(ethylene glycol) (PEG) is widely considered the gold standard of biocompatible polymers in a vast variety of medical and pharmaceutical applications due to its high solubility in aqueous solution and chemical inertness. However, modification of the chain structure of PEG by copolymerization of ethylene oxide (EO) with other epoxide monomers is a synthetically demanding task, requiring rigorous safety precautions and synthetic expertise due to the toxic, flammable, and gaseous nature of the monomer EO.…”

Cascade Ring Strain Release Polymerization of Cyclohexene Oxide and Derivatives Using a Mono(μ-Alkoxo)bis(alkylaluminum) Initiator

“…Molecular weight control and functional group tolerance make this system well-suited for producing previously inaccessible compositions and architectures. Despite the functional group tolerance these catalysts and other catalytic systems have demonstrated, most materials development efforts use terminal epoxides such as ethylene oxide, alkylene oxides, or derivatives of epichlorohydrin such as the glycidyl ethers. ,, The scope of typical monomers is due to the availability of the alkylene oxides and the ease with which epichlorohydrin may be used to glycidylate nearly any alcohol under mild reaction conditions . An alternative monomer platform based on, for example, a highly strained CHO could increase polymerization rates relative to terminal epoxides, increase glass-transition temperature ( T g ) of the resulting polymers, and expand the scope of new polyether materials.…”