Covalent and electrostatic incorporation of amines into hypercrosslinked polymers for increased CO2 selectivity

Two methods of incorporating functional groups rich in nitrogen into low cost microporous hypercrosslinked polymers (HCPs) have been evaluated and the effects on the carbon dioxide CO₂/N₂ IAST selectivity were measured. Electrostatic incorporation of an ammonium salt into a sulfonic acid-containing HCP polymer afforded a static CO₂ uptake of 2.5 mmol g⁻¹ with a CO₂/N₂ IAST selectivity of 42:1 at 1 bar and 298 K. Using column breakthrough measurements with a 15:85 CO₂/N₂ mixture at 298 K and 1 bar, a selectivity of 17:1 was obtained. However, varying the counterion resulted in polymers with lower CO₂/N₂ selectivity values. Decoration of the parent polymer with CO₂-philic imidazole followed by electrostatic ammonium salt incorporation blocked some of the micropores reducing the selectivity which re-emphasizes the role and importance of pore width for CO₂/N₂ selectivity. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2513–2521     

Postsynthetic amine modification of porous organic polymers for CO2 capture and separation

Porous organic polymers (POPs) constitute an important class of sorbents studied in various adsorption and separation processes. Their unique properties, including high surface areas, adjustable pore sizes, and surface chemistries make them ideal candidates for CO₂ capture. To achieve a high CO₂ adsorption capacity and selectivity, particularly at the low partition pressures required for post-combustion CO₂ capture or direct capture of CO₂ from the atmosphere, incorporating amines onto the polymer frameworks or within the pores has shown much promise. This review provides a comprehensive summary of recent studies on the synthesis and CO₂ capture performance of amine-functionalized POPs. The review also provides a detailed discussion of structure-performance relationships, focusing on how the loading amount and amine type influence CO₂ capture capacity, CO₂/N₂ selectivity, heat of adsorption, sorption kinetics, and recyclability of POPs. Additionally, the authors offer their perspective on the challenges associated with the practical implementation of amine-modified POPs for CO₂ capture.     

Synthesis of Two‐dimensional Microporous Carbonaceous Polymer Nanosheets and Their Application as High‐performance CO2 Capture Sorbent

The synthesis of two‐dimensional (2D) polymer nanosheets with a well‐defined microporous structure remains challenging in materials science. Here, a new kind of 2D microporous carbonaceous polymer nanosheets was synthesized through polymerization of a very low concentration of 1,4‐dicyanobenzene in molten zinc chloride at 400–500 °C. This type of nanosheets has a thickness in the range of 3–20 nm, well‐defined microporosity, a high surface area (～537 m² g^?1), and a large micropore volume (～0.45 cm³ g^?1). The microporous carbonaceous polymer nanosheets exhibit superior CO₂ sorption capability (8.14 wt % at 298 K and 1 bar) and a relatively high CO₂ selectivity toward N₂ (25.6). Starting from different aromatic nitrile monomers, a variety of 2D carbonaceous polymer nanosheets can be obtained showing a certain universality of the ionothermal method reported herein.     

Fabrication of photo‐cross‐linked polyethyleneimine‐based barriers for CO2 capture

In this study, first, polyethyleneimine was acrylated and mixed with polyvinyl alcohol solution to prepare photo‐crosslinked polyethyleneimine (PEI)‐based nanofibers by utilizing ultraviolet and electrospinning technique at the same time. For CO₂ permeability testing, same formulations were prepared by using solvent casting technique and exposed to ultraviolet light to have polyethyleneimine‐based membrane films. The chemical structures of the nanofibers were characterized by Fourier transform infrared spectroscopy. The thermal properties of nanofibers were examined by thermal gravimetric analysis and differential scanning calorimeter. The morphology of nanofibers was investigated by scanning electron microscopy. CO₂ permeabilities of samples were also measured. Copyright © 2015 John Wiley & Sons, Ltd.     

Triptycene‐Based Microporous Polymer with Pending Tetrazole Moieties for CO2‐Capture Application

Triptycene‐based micorporous polymer is functionalized with CO₂‐philic tetrazole moieties via ZnCl₂‐catalyzed post‐polymerization. Gas adsorption experiments indicate that it possesses high CO₂ uptake capacity, reaching 134 cm³ g⁻¹ (26.5 wt%) at 1.0 bar and 273 K, along with high selectivity towards CO₂ over N₂ and CH₄. The porous polymeric networks present the promising potentials as efficient adsorbents in clean energy applications.

     

Solid‐state 13C, 15N and 29Si NMR characterization of block copolymers with CO2 capture properties

Natural abundance solid‐state multinuclear (¹³C, ¹⁵N and ²⁹Si) cross‐polarization magic‐angle‐spinning NMR was used to study structures of three block copolymers based on polyamide and dimethylsiloxane and two polyamides, one of which including ferrocene in its structure. Assignment of most of the resonance lines in ¹³C, ¹⁵N and ²⁹Si cross‐polarization magic‐angle‐spinning NMR spectra were suggested. A comparative analysis of ¹³C isotropic chemical shifts of polyamides with and without ferrocene has revealed a systematic shift towards higher δ ‐values (de‐shielding) explained as the incorporation of paramagnetic ferrocene into the polyamide backbone. In addition, the ¹³C NMR resonance lines for ferrocene‐based polyamide were significantly broadened, because of paramagnetic effects from ferrocene incorporated in the structure of this polyamide polymer. Single resonance lines with chemical shifts ranging from 88.1 to 91.5 ppm were observed for ¹⁵N sites in all of studied polyamide samples. ²⁹Si chemical shifts were found to be around ?22.4 ppm in polydimethylsiloxane samples that falls in the range of chemical shifts for alkylsiloxane compounds. The CO₂ capture performance of polyamide‐dimethylsiloxane‐based block copolymers was measured as a function of temperature and pressure. The data revealed that these polymeric materials have potential to uptake CO₂ (up to 9.6 cm³ g^?1) at ambient pressures and in the temperature interval 30–40 °C. Copyright © 2016 John Wiley & Sons, Ltd.     

Effective enhancement of selectivities and capacities for CO2 over CH4 and N2 of polymers of intrinsic microporosity via postsynthesis metalation

A series of metalized C-PIM-M (M = Na⁺, Mg²⁺, Al³⁺, PIMs = polymers of intrinsic microporosity) materials were prepared from a carboxyl-functionalized PIM (C-PIMs). The C-PIM-Na exhibited a high CO₂ adsorption capacity of 2.44 mmol/g and extreme low CH₄ uptake of 0.28 mmol/g at 273 K and 101 kPa among three metallated PIMs. It showed remarkably high CO₂/CH₄ and CO₂/N₂ selectivities at both 273 and 293 K due to an advantageous pore-blocking effect of Na⁺ cation.     

UV‐triggered CO2‐responsive behavior of nanofibers and their controlled drug release properties

A novel nanofibrous mat featuring an ultraviolet (UV)‐induced CO₂‐responsive behavior was fabricated via electrospinning and used as a controlled drug release system. First, a random copolymer for electrospinning, poly(N,N‐diethylaminoethyl acrylamide‐co‐N‐benzylacrylamide‐co‐N,N‐dimethyl‐N‐(2‐nitrobenzyl)‐ethaneamine acrylamide‐co‐4‐acryloyloxy benzophenone) [P(DEEA‐co‐BA‐co‐DMNOBA‐co‐ABP)], was prepared based on pentafluorophenyl esters via an “active ester‐amine” chemistry reaction. Subsequently, doxorubicin hydrochloride (DOX)‐loaded P(DEEA‐co‐BA‐co‐DMNOBA‐co‐ABP) nanofibers were fabricated, yielding a new drug‐loaded nanofibrous mat as a potential wound dressing. These DOX‐loaded nanofibers can respond to UV irradiation and CO₂ stimulation. Interestingly, without UV irradiation, the fabricated nanofibers cannot exhibit any responsiveness. Therefore, the majority of the DOX was steadily stored in the nanofibers, even in the presence of CO₂. However, upon UV irradiation, the CO₂‐responsive behavior of the nanofibers was activated and the prepared nanofibers swelled slightly, resulting in the release of around 42% DOX from the nanofibers. Upon further purging with CO₂, the release amount of DOX from the nanofibers could reach up to approximately 85%, followed by the morphological transition from a nanofibrous mat to a porous hydrogel film. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1580–1586     

CO2‐Breathing Induced Reversible Activation of Mechanophore within Microgels

In this work, CO₂‐breathing induced reversible activation of mechanophore within microgels is reported. The microgels are prepared through soap‐free emulsion polymerization of CO₂‐switchable monomer 2‐(diethylamino)ethyl‐methacrylate, using spiropyran (SP) based mechanophore MA‐SP‐MA as cross‐linker. The microgels can be swollen by CO₂ aeration. The swelling of microgels activates the SP mechanophore into merocyanine, causing distinguished color and fluorescence change. Moreover, these transitions are highly reversible, and the initial states of microgels can be easily recovered by “washing off” CO₂ with N₂. The present contribution represents the first example of CO₂‐breathing activation of mechanophore within microgels.

     

Synthesis and characterization of fluorescently labeled core cross‐linked star polymers

A series of fluorescently labeled core cross‐linked star (CCS) polymers were synthesized via the “arm‐first” approach, employing atom transfer radical polymerization (ATRP) to control the resulting architecture. The initiator p‐toluenesulfonyl chloride (TsCl) was used to synthesize “living” poly(methyl methacrylate) (PMMA) macroinitiator, which was subsequently cross‐linked to generate the CCS polymers. Divinylbenzene (DVB) was used as the cross‐linker and 7‐[4‐(trifluoromethyl)coumarin] methacrylamide ( F₁ , λ_ex = 343 nm) was added as a fluorescent labeling monomer. A range of PMMA/DVB/ F₁ based CCS polymers were synthesized with the core domain made selectively fluorescent by using varying amounts of monomer F₁ . The core functionalized stars were characterized using gel permeation chromatography (GPC) equipped with multi‐angle laser light scattering (MALLS), refractive index (RI), and UV–visible detectors. The fluorescence quantum yield (Φ_F) and the amount of fluorescent monomer incorporated into the core were quantified by UV–visible and fluorescence spectrophotometry. It was recognized that the overall molecular weights of the stars produced, along with their core molecular weight, decreased as the mol % of monomer F₁ was increased relative to cross‐linker. Visual confirmation of F₁ incorporation was obtained by fluorescence microscopy of thin polymer films cast on glass substrates. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2422–2432, 2008     

CO2 Fixation into Novel CO2 Storage Materials Composed of 1,2‐Ethanediamine and Ethylene Glycol Derivatives

A new CO₂ fixation process into solid CO₂‐storage materials (CO₂SMs) under mild conditions has been developed. The novel application of amine–glycol systems to the capture, storage, and utilization of CO₂ with readily available 1,2‐ethanediamine (EDA) and ethylene glycol derivatives (EGs) was demonstrated. Typically, the CO₂SMs were isolated in 28.9–47.5 % yields, followed by extensive characterization using ¹³C NMR, XRD, and FTIR. We found that especially the resulting poly‐ethylene‐glycol‐300‐based CO₂SM (PCO₂SM) product could be processed into stable tablets for CO₂ storage; the aqueous PCO₂SM solution exhibited remarkable CO₂ capturing and releasing capabilities after multiple cycles. Most importantly, the EDA and PEG 300 released from PCO₂SM were found to act as facilitative surfactants for the multiple preparation of CaCO₃ microparticles with nano‐layer structure.     

膜吸收-再生循环技术捕集CO_2操作性能及其参数优化研究

采用N-甲基二乙醇胺(MDEA)+哌嗪(PZ)复合溶液作为捕集CO2吸收剂,研究了膜吸收-再生循环装置的操作性能,考察了气液流量、吸收剂浓度和再生电压等因素对捕集率和传质通量的影响,采用正交实验方法,优化操作条件,确定最佳操作方案。结果表明,气体流量对捕集率的影响明显大于液体流量的影响;气体流量增大对传质通量影响不明显;吸收剂浓度的增大使传质通量迅速增大,但大于一定值时通量不再增大;正交实验得出最佳操作条件为液体流量110 mL/min、气体流量0.65 L/min、吸收剂总浓度2.5 mol/L和再生电压210 V,捕集率大于95%,传质通量维持在5.86×10-4mol/(m2.s)。     

Synthesis and characterization of thiazolothiazole‐based polymers and their applications in polymer solar cells

A novel series of thiazolothiazole (Tz)‐based copolymers, poly[9,9‐didecylfluorene‐2,7‐diyl‐alt‐2,5‐bis‐(3‐hexylthiophene‐2‐yl)thiazolo[5,4‐d]thiazole] (P1), poly[9,9‐dioctyldibenzosilole‐2,7‐diyl‐alt‐2,5‐bis‐(3‐hexylthiophene‐2‐yl)thiazolo[5,4‐d]thiazole] (P2), and poly[4,4′‐bis(2‐ethylhexyl)‐dithieno[3,2‐b:2′,3′‐d]silole‐alt‐2,5‐bis‐(3‐hexylthiophene‐2‐yl)thiazolo[5,4‐d]thiazole] (P3), were synthesized for the use as donor materials in polymer solar cells (PSCs). The field‐effect carrier mobilities and the optical, electrochemical, and photovoltaic properties of the copolymers were investigated. The results suggest that the donor units in the copolymers significantly influenced the band gap, electronic energy levels, carrier mobilities, and photovoltaic properties of the copolymers. The band gaps of the copolymers were in the range of 1.80–2.14 eV. Under optimized conditions, the Tz‐based polymers showed power conversion efficiencies (PCEs) for the PSCs in the range of 2.23–2.75% under AM 1.5 illumination (100 mW/cm²). Among the three copolymers, P1, which contained a fluorene donor unit, showed a PCE of 2.75% with a short‐circuit current of 8.12 mA/cm², open circuit voltage of 0.86 V, and a fill factor (FF) of 0.39, under AM 1.5 illumination (100 mW/cm²). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Hierarchically Mesoporous o‐Hydroxyazobenzene Polymers: Synthesis and Their Applications in CO2 Capture and Conversion

The synthesis of hierarchically mesoporous polymers with multiple functionalities is challenging. Herein we reported a template‐free strategy for synthesis of phenolic azo‐polymers with hierarchical porous structures based on diazo‐coupling reaction in aqueous solution under mild conditions. The resultant polymers have surface areas up to 593 m² g^?1 with the mesopore ratio of >80 %, and a good ability to complex with metal ions, such as Cu²⁺, Zn²⁺,Ni²⁺, achieving a metal loading up to 26.24 wt %. Moreover, the polymers complexed with Zn showed excellent performance for catalyzing the reaction of CO₂ with epoxide, affording a TOF of 2570 h^?1 in the presence of tetrabutyl ammonium bromide (7.2 mol %). The polymer complexed with Cu could catalyze the oxidation of alcohol with high efficiency.     

Poly(2‐hydroxyethyl methacrylate‐co‐N,O‐dimethacryloylhydroxylamine) particles by dispersion polymerization

Poly(2‐hydroxyethyl methacrylate‐co‐N,O‐dimethacryloylhydroxylamine) particles were prepared by dispersion polymerization in toluene/2‐methylpropan‐1‐ol medium using cellulose acetate butyrate and dibenzoyl peroxide (BPO) as a steric stabilizer and initiator, respectively. The particle size was reduced with decreasing solvency of the reaction medium (more nuclei were generated) because the critical chain length of the precipitated oligomers decreased with an increasing toluene content, which is a poorer solvent for the polymer than 2‐methylpropan‐1‐ol. There is an optimum initiator concentration (2 wt % BPO relative to monomers) for producing low‐polydispersity particles under given conditions. Additionally, discrete spherical particles were obtained at a low monomer concentration and/or higher polymerization temperature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1625–1632, 2002     

Efficient CO2 Capture and Photoreduction by Amine‐Functionalized TiO2

Amine‐functionalization of TiO₂ nanoparticles, through a solvothermal approach, substantially increases the affinity of CO₂ on TiO₂ surfaces through chemisorption. This chemisorption allows for more effective activation of CO₂ and charge transfer from excited TiO₂, and significantly enhances the photocatalytic rate of CO₂ reduction into methane and CO.     

Synthesis of polymers containing 1,2,4‐oxadiazole as an electron‐acceptor moiety in their main chain and their solar cell applications

To explore the aptitude of 1,2,4‐oxadiazole‐based electron‐acceptor unit in polymer solar cell applications, we prepared four new polymers (P1–P4) containing 1,2,4‐oxadiazole moiety in their main chain and applied them to solar cell applications. Thermal, optical, and electrochemical properties of the polymers were studied using thermogravimetric, absorption, and cyclic voltammetry analysis, respectively. All four polymers showed high thermal stability (5% degradation temperature over 335 °C), and the optical band gaps were calculated to be 2.20, 1.72, 1.37, and 1.74 eV, respectively, from the onset wavelength of the film‐state absorption band. The energy levels of the polymers were found to be suitable for bulk heterojunction (BHJ) solar cell applications. The BHJ solar cells were prepared by using the synthesized polymers as a donor and PC₇₁BM as an electron acceptor with the configuration of ITO/PEDOT:PSS/polymer:PC₇₁BM (1:3 wt %)/LiF/Al. One of the polymers was found to show the maximum power conversion efficiency of 1.33% with a Jsc of 4.95 mA/cm², a V_oc of 0.68 V, and a FF of 40%, measured using AM 1.5 G solar simulator at 100 mW/cm₂ light illumination. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013