Next Article in Journal
New Trends in the Methodologies of Determination of Benzodiazepine Residues in Biological Samples
Next Article in Special Issue
Polymer-Coated Nickel Nanoparticles for CO2 Capture in Seawater
Previous Article in Journal
Comparison of CuCl/NaY and CuCl/AC Process Performance Using a Vacuum Pressure Swing Adsorption Simulation
Previous Article in Special Issue
Enhancing SO3 and Fine Particle Co-Removal in Low-Low Temperature Electrostatic Precipitation via Turbulent Agglomeration
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Separations
Volume 12
Issue 4
10.3390/separations12040094
separations-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Porous Composite Polymers Composed of Polyethyleneimine and Cyclodextrins: Synthesis and Application as Adsorbents for an Organic Compound

by
Naofumi Naga
1,2,*,
Yuma Miyazaki
2 and
Tamaki Nakano
3,4
1
Shibaura Institute of Technology, College of Engineering, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan
2
Graduate School of Science & Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan
3
Institute for Catalysis and Graduate School of Chemical Sciences and Engineering, Hokkaido University, N 21, W 10, Kita-ku, Sapporo 001-0021, Japan
4
Integrated Research Consortium on Chemical Sciences, Institute for Catalysis, Hokkaido University, N 21, W 10, Kita-ku, Sapporo 001-0021, Japan
*
Author to whom correspondence should be addressed.
Separations 2025, 12(4), 94; https://doi.org/10.3390/separations12040094
Submission received: 10 March 2025 / Revised: 3 April 2025 / Accepted: 7 April 2025 / Published: 10 April 2025
(This article belongs to the Special Issue Application of Advanced Materials and Technologies in the Separation and Adsorption)
Browse Figures
Versions Notes

Abstract

:
Polyethyleneimine-based porous composites have been prepared by ring-opening polymerization of 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] (3AZ), a tri-aziridine compound, in water, in the presence of cyclodextrins (CDs), i.e., α-CD, γ-CD, methyl-β-cyclodextrin (Me-β-CD), monoacetyl-β-cyclodextrin (Ac-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD). The corresponding 3AZ-CD porous polymer composites were successfully obtained in most cases under a wide range of CD concentrations, 5–20 wt%, and reaction temperatures, 20–60 °C. The reaction system in the presence of Ac-β-CD preferentially yielded gels. The polymer composites were composed of connected particles with sizes of the order of 10−9 m. The particle sizes decreased with an increase in the CD concentration. Young’s moduli of the 3AZ-CD porous polymer composites tended to increase with an increase in bulk density. The 3AZ-CD porous polymer composites with Me-β-CD and HP-β-CD effectively adsorbed phenolphthalein in the solution. The adsorption value increased with increasing the CD content and rose to more than 600 mg/g of porous polymer composite.

1. Introduction

Molecular recognition is one of the most distinctive features of biochemistry. This function is induced by various interactions between molecules, such as hydrogen bonding, coordination bonding, hydrophilic effects, van der Waals forces, π-π stacking, halogen bonding, electrostatic forces, and so on. Host–guest chemistry is a fundamental mechanism for static molecular recognition. Molecular imprinting has been widely studied for molecular recognition in artificial chemical systems and used to fabricate polymers called molecular imprinting polymers (MIPs) that can recognize not only the imprinted molecules but also those with similar structures [1,2,3,4,5,6,7,8,9,10,11,12,13]. Clathration, or inclusion, is another mechanism for molecular recognition that is well known for cyclodextrins (CDs). CDs can form non-covalent complexes with organic molecules within their cyclic structure, which features a hydrophobic inner cavity composed of glucose units linked by α-1,4-glycosidic bonds [14,15,16,17]. This characteristic molecular structure of CDs makes it possible to clathrate various organic molecules.
Porous polymers are useful materials for separation processes due to their co-continuous structure with a high surface area [18,19,20,21,22,23,24]. Various porous polymers have been synthesized by polymerization-induced phase separation (PIPS) and have been used mainly as packing for chromatography (columns, filters, and discs), exhibiting high separation ability based on their co-continuous porous structure [25,26,27,28,29,30]. The complex conjugation of porous polymers with functional materials is used to improve the separation ability and add new functions. PIPS in the presence of the composite materials should make it possible to prepare composite porous polymers. The following two characteristics would be required for the composite materials. One is homogeneous dispersibility in the reaction system to form the homogeneous porous polymer. The corresponding solution or sol with the solvent used in the PIPS is preferable. Another is that the composite materials do not inhibit phase separation during the polymerization. Additives in the PIPS system sometimes inhibit phase separation, yielding a gel without a porous structure.
Composite polymers with CD derivatives should be a useful method to add characteristic functions derived from CDs to polymer materials. The surface modification of fibers with a reactive CD, monochloro-triazinyl-β-CD (MCT-β-CD) achieved through a chemical reaction successfully produced fabrics with β-CD moieties [31]. The development of a facile method to prepare the porous polymer composites with CDs should increase the separation performance and applicability of the polymer material.
We previously reported a facile synthesis method to prepare a polyethyleneimine-based porous polymer by ring-opening polymerization of a tri-aziridine derivative in water [32]. Dissolution of 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] (3AZ) in water initiated cationic ring-opening polymerization, induced phase separation and successfully yielded a porous polymer. This reaction should be applicable to prepare porous polymers in the presence of the composite materials that are soluble and/or dispersible in water. As the next step, we came up with the idea of producing 3AZ porous composite polymer with CDs. Among the conventional CDs, α-CD and γ-CD are soluble in water. Although β-CD is almost insoluble in water, water-soluble substituted-β-CD derivatives can be applicable to this reaction system.
In this study, polyethyleneimine-based porous composite polymers were synthesized by the ring-opening polymerization of 3AZ in CD solutions (Scheme 1). Polyethyleneimine-based porous composite polymers with α-CD, γ-CD, and substituted-β-CD derivatives were successfully obtained. The obtained porous composite polymers containing CDs may be useful in the separation and adsorption of organic compounds because CDs can capture molecules in their hydrophobic inner cavities. The porous composite polymers with substituted-β-CD compounds were found to effectively adsorb phenolphthalein, as model organic compounds, via a host–guest mechanism.

2. Materials and Methods

2.1. Materials

2,2-Bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] (3AZ) was kindly donated by Nippon Shokubai Co., Ltd., (Osaka, Japan) and used as received. α-CD, γ-CD, and methyl-β-cyclodextrin (Me-β-CD, Fuji-film Wako Pure Chemical Industries, Osaka, Japan), monoacetyl-β-cyclodextrin (Ac-β-CD, Junsei Chemical Co., Ltd., Tokyo, Japan), and hydroxypropyl-β-cyclodextrin (HP-β-CD, Kanto Chemical Co., Inc., Tokyo, Japan) were commercially obtained and used as received. Methanol (MeOH), ethanol (EtOH), phenolphthalein (phph), and sodium carbonate were commercially obtained from Kanto Chemical Co., Inc., and used without further purification.

2.2. Synthesis of Porous Polymer Composites

The reaction of 20 wt% 3AZ in the presence of 5 wt% CD is described as an example. A CD (0.25 g) and distilled water (3.75 g) were added to a 20 mL vial and stirred by a vortex mixer (Mixer N-40M-1, NISSIN, Tokyo, Japan) for a few minutes to make a homogeneous solution. 3AZ (1.0 g) and the CD solution were added to a quadrangular prism polyethylene bottle (1.7 cm × 1.7 cm × 3.0 cm), stirred using a vortex mixer, and then stored at the desired temperature in an ESPEC SU-641 constant temperature chamber (ESPEC CORP., Osaka, Japan) for 24 h. The obtained porous polymer composite was washed by immersion in an excess of methanol for 24 h. The porous polymer composite was air-dried at room temperature for 72 h and further dried in vacuo at 40 °C for 4 h. Reactions with different monomer concentrations were conducted by the same procedures.

2.3. Adsorption Test of Phph

Solutions with different concentrations of phph, 10, 20, 42, 62, 82 mg/L in Na2CO3 aq. (20.0 g/L) pH: 11.3 were prepared for the adsorption test. A cubic sample of a porous polymer composite (0.7 × 0.7 cm × 0.7 cm) was soaked into a 10 mL of phph solution for 24 h at 25 °C. The concentration of phph in the solution after adsorption was determined by a UV–vis spectrum using a calibration curve. The adsorption value (qe) was calculated using Equation (1) below.
qe (mg/g) = {Ce [mg/L] − Co [mg/L]} × V [L]/m [g]
Co: phph concentration before adsorption
Ce: phph concentration after adsorption
V: volume of phph solution used (=10 mL)
m: weight of porous polymer composite used

2.4. Analytical Procedures

FT-IR spectra of porous composite polymers and CDs were recorded on a FTIR-8400 or an IRAffinity-1S spectrometer (SHIMADZU Corporation, Kyoto, Japan), and 30 scans were accumulated from 4000 to 500 cm−1.
Scanning electron microscopy (SEM) images or SEM/energy dispersive X-ray spectroscopy of 3AZ-CD porous polymer composites were acquired by a JEOL JSM-7610F microscope (Tokyo, Japan) with a LEI detector at an acceleration voltage of 3.0 kV or 20 kV, respectively. The nitrogen (N) content was determined by the atomic number (Z)–absorption (A)–fluorescence (F) (ZAF) correction method. The size of the particles in the SEM images was evaluated by image analysis using an Image-J software package.
The mechanical properties of the porous polymer composites were investigated using the compression test with a Tensilon RTE-1210 apparatus (ORIENTEC Co., Ltd., Tokyo, Japan). The test samples were cut into a 1 cm3 cube and pressed at a rate of 0.5 mm/min at room temperature. The bulk density of the porous polymer composite, g/cm3,was calculated from the wight of the samples before the test. The porosity of the porous polymer composite was calculated using Equation (2).
Porosity (%) = {1.0 − true volume of polymer (Vp) & CDs (Vcd) cm3/porous polymer composite (cm3)} × 100
Vp = {bulk density (g/cm3) × 3AZ polymer in composite (wt%)/100}/{true density of 3AZ polymer (g/cm3)}
Vcd = {bulk density (g/cm3) × CD in composite (wt%)/100}/{true density of CD (g/cm3)}
UV–vis spectra of phenolphthalein (phph) solutions were recorded on a UV2450 spectrometer (SHIMADZU Corporation, Kyoto, Japan).

3. Results and Discussion

3.1. Synthesis of 3AZ-CD Porous Polymer Composites

Ring-opening polymerizations of 3AZ (20 wt%) were conducted in water in the presence of 5–20 wt% CDs at 20–60 °C. Most of the reaction systems yielded porous polymers over a wide range of temperatures and CD concentrations. The reaction systems with Ac-β-CD preferentially yielded the gel, and a corresponding porous polymer was obtained under the reaction conditions of 5 wt% Ac-β-CD at 60 °C.
These results can be explained by the affinity between the polymer network formed by the ring-opening polymerization of 3AZ and the solvent, based on their solubility parameter (SP) values. Two molecules with small difference in SP values show high affinity and compatibility. The solvent of the reaction system is the CD solution, water + CD. The SP value of water, 47.8 MPa1/2, is much higher than those of CDs, α-CD: 31–34 MPa1/2, β-CD: 29–33 MPa1/2, γ-CD: 27–31 MPa1/2. The addition of CDs to water should decrease the SP value of the solvent, bringing it closer to that of polyethyleneimine backbone, 30–35 MPa1/2, formed by the polymerization of 3AZ. In the case of the reaction with Ac-β-CD, the modification of the OH group of β-CD by the Ac group effectively decreases the SP value of the solvent and increases the affinity between the polymer network and the solvent. As a result, the phase separation rate was drastically decreased, with an increase in the Ac-β-CD concertation. As mentioned above, the porous structure of polyethyleneimine is formed by polymerization-induced phase separation via spinodal decomposition processes. The 3AZ in the Ac-β-CD system should be fixed before the phase separation to yield gel in the end.

3.2. Structure and Properties of 3AZ-CD Porous Polymer Composites

3.2.1. Composition and Morphology

FT-IR spectra of the 3AZ-CD porous polymer showed the profiles overlapping with those of 3AZ and CD, indicating a blend of 3AZ and CD without interaction (Figure S1). However, the spectra were insufficient for quantitative analysis of the compositions. The CD contents in 3AZ-CD porous polymer composites (obtained from reactions with 20 wt% of 3AZ at 20 °C) were quantitatively evaluated by SEM-EDX based on the nitrogen (N) content. A 3AZ porous polymer without CD (entry 0) contains 15.1 wt% of nitrogen. The CD content in the 3AZ-CD porous polymer composite can be calculated using Equation (3) below.
CD content (wt%) = {15.1 − N content (wt%)}/15.1 × 100
The CD content in the 3AZ-CD porous polymer composite increased with increasing CD feed in the reaction system (Table 1). There was not a significant difference in the contents between the CDs.
The surface morphology of the 3AZ-CD porous polymer composites was observed by SEM. The SEM images of the 3AZ-CD porous polymer composites prepared at 20 °C with an average particle size (diameter) are shown in Figure 1. The porous polymer composites showed surface morphologies composed of connected particles. The average particle size of the porous polymer composites tended to decrease with an increase in the CD content and increase with increasing reaction temperature (Figures S2–S5). The size ranged from a few micrometers to the order of sub-nanometers, and the polymers may be regarded as nanocomposites.
The porous structure in the composites should be formed by polymerization-induced phase separation via spinodal decomposition processes. The morphology of the porous polymer depends on the fixation stage of the phase separation, as shown in Figure 2. When the system is fixed during the first stage of the phase separation (Figure 2b) the co-continuous monolithic structure is formed. This phase-separated structure transforms into connected drops due to the interfacial tension (Figure 2c) and the spheres grow large (Figure 2d) as the phase separation progresses (the second stage). The porous morphology composed by the connected particles should be formed by the fixation of the phase separation structure during these stages. In cases where phase separation proceeds too quickly, the precipitates are obtained at the bottom of the reaction vessel (Figure 2e). The morphologies in most of the 3AZ-CD porous polymer composites should be completed at the phase separation stages, corresponding to Figure 2c,d. The reaction conditions should affect both the network formation (polymerization) rate (Rp) and phase separation rate (Rs). The morphology of the porous polymer prepared by the polymerization-induced phase separation should be affected by the relative ratio of the polymerization to phase separation (Rp/Rs). The increase in the CD contents in the polymerization systems should preferentially accelerate the network formation (increase Rp) and fix the systems at the earlier period of the second stage in the phase separation (Figure 2c). By contrast, the higher reaction temperature should be more effective in increasing the phase separation rate (Rs), which causes the growth of the particles, as observed in the porous polymers fixed at the later second stage, Figure 2d.

3.2.2. Mechanical Properties

Incompatible complex combinations in polymer nanocomposites sometime induces brittleness in the materials. The mechanical properties of the 3AZ-CD porous polymer composites were evaluated using the compression test to investigate the effect of CD. Figure 3 shows the stress–strain (s-s) curves of 3AZ-HP-β-CD porous polymer composites. Young’s moduli, determined from the initial slope of the s-s curves, are summarized in Table 1. All the 3AZ-CD porous polymer composites were unbreakable under the compression of 40 N. The Young’s modulus increased with increasing the CD content in the porous polymer composites. The result can be explained by the increase in bulk density caused by the small size of the particles with increasing CD content, as observed in SEM images (Figure 1). The profile with a slope changes (two steps deformation) in the s-s curves indicates consequent deformation derived from the compression of the vacant spaces following the particles.

3.3. Adsorption Test of Phph

The macrocyclic structure of CDs can include small organic molecules, especially with hydrophobic features. The CDs are composed by 6–8 glucose units, which have cavity diameters of about 0.45–0.6 nm in α-CD, 0.6–0.8 nm in β-CD, and 0.8–0.95 nm in γ-CD. These structures are suitable for the capture of organic compounds with the corresponding sizes. In the present study, we tested adsorption of some dyes from the solutions by the 3AZ-CD porous polymer composites. In most cases, the adsorption value of the dye was independent of the CDs content in the porous polymer composites. For example, methyl orange was adsorbed by all the 3AZ-CD porous polymer composites, and even the 3AZ porous polymer without CD adsorbed an almost constant amount (about 900 mg/g), indicating direct adsorption onto the 3AZ polymer network. By contrast, phph was not adsorbed by any 3AZ-α-CD and 3AZ-γ-CD porous polymer composites. We found selective adsorption of phph (related to the CD concentration) by the porous polymer composites containing β-CD-based CDs, including Me-β-CD and HP-β-CD. Figure 4i shows UV–vis spectra of the phph original solution and the solutions after immersion of the 3AZ-HP-β-CD porous polymer composites at 25 °C for 24 h. The absorbance peak intensity at 554 nm derived from phph decreased with increasing CD content in the porous polymer composites. The adsorption value of phph per unit weight of the porous polymer composite (qe: mg/g) increased with an increase in CD content, as summarized in Table 2. By contrast, the immersion of the 3AZ porous polymer without CD (for reference) did not decrease the absorbance peak intensity. These results make it clear that phph was adsorbed by the β-CDs in the porous polymer composites. The adsorption tests were conducted in the phph solutions with different concentrations (10–82 mg/L) to fit Langmuir and Freundlich adsorption isotherm equations, as shown in Figure 4ii. The Freundlich adsorption might be rather appropriate for the adsorption of phph. When the incorporated CDs were homogeneously immobilized on the adsorption surface, the plots tended to fit the Langmuir adsorption isotherm. One explanation of the result is the inhomogeneous composition of β-CD-based CDs in the porous polymer [33,34,35]. Figure 5 shows a plausible model of phph adsorption by 3AZ-Me-β-CD and HP-β-CD. A phph molecule is adsorbed by one β-CD moiety. The present 3AZ-CD porous polymer composites were prepared from corresponding homogeneous CD solutions. Although the CD should be distributed homogeneously in the porous polymer composites, the random incorporation in the disordered porous structure should cause inactive CD moieties, which cannot adsorb phph molecules, and induce inhomogeneity on the adsorption surface of the 3AZ-Me-β-CD and HP-β-CD porous polymer composites.

4. Conclusions

The ring-opening polymerization of a 3AZ in the presence of CD solutions successfully yielded polyethyleneimine-based porous polymer composites. The porous structures were composed of connected particles formed through polymerization-induced phase separation via a spinodal decomposition process, and their size tended to decrease with increasing CD feed in the reaction system. The Young’s moduli of the porous polymer composites increased with increasing CD content, accompanied by an increase in their bulk densities. The porous polymer composites containing Me-β-CD and HP-β-CD selectively and effectively adsorbed phph from the solution, with more than 600 mg/g porous polymer composites, which obeyed the Freundlich adsorption isotherm. The Freundlich adsorption isotherm was better obeyed for the adsorption of phph due to the inhomogeneous composition of β-CD-based CDs in the porous polymer. The random incorporation in the disordered porous structure, causing inactive CDs, might be a possible explanation for the results.
The present molecular design of porous polymer composites is usable for producing a separation material for a selective molecule from its solution. The high liquid permeability of the porous structure is a preferable feature for the application in separation columns and filters. Porous polymer composites with selective molecular capture should be usable, as well as MIPs. As the next step, we are preparing porous polymer composites that can separate some molecules using the chiral selective capture function. These investigations are now underway, and the results will be reported elsewhere in due course.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/separations12040094/s1, Figure S1: FT-IR spectra of (a) 3AZ porous polymer (entry 0), (b) α-CD, and (c) 3AZ-α-CD porous polymer composite. 3AZ in feed: 20 wt%; α-CD in feed: 10 wt% (entry 2). Figure S2: SEM image of 3AZ porous polymer. 3AZ monomer concentration in the reaction solution: 20 wt%, (entry 0). Figure S3: SEM images of 3AZ-α-CD porous polymer composites. 3AZ in feed: 20 wt% Figure S4: SEM images of 3AZ-γ-CD porous polymer composites. 3AZ in feed: 20 wt%. Figure S5: SEM images of 3AZ-Me-β-CD porous polymer composites. 3AZ in feed: 20 wt%. Figure S6: SEM images of 3AZ-HP-β-CD porous polymer composites. 3AZ in feed: 20 wt%. Figure S7: SEM image of 3AZ-Ac-β-CD porous polymer composite. Ac-β-CD concentration: 5.0 wt%; 3AZ monomer concentration: 20 wt% in the reaction solution; reaction temperature: 60 °C.

Author Contributions

Conceptualization, N.N. and T.N.; investigation, Y.M. and N.N.; analysis, Y.M., N.N. and T.N.; writing—original draft preparation, N.N.; writing—review and editing, T.N.; supervision, N.N. and T.N.; project administration, N.N.; funding acquisition, N.N. and T.N. All authors have read and agreed to the published version of the manuscript.

Funding

This work was partially supported by ICAT, Hokkaido University thorough the Joint Usage/Research Center for Catalyst grant.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available in the article or in the Supplementary Material here.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. BelBruno, J.J. Molecular Imprinted Polymers. Chem. Rev. 2019, 119, 94–119. [Google Scholar] [CrossRef] [PubMed]
  2. Mostafa, A.M.; Barton, S.J.; Wren, S.P.; Barker, J. Review on molecular imprinted polymers with a focus on their application to the analysis of protein biomarkers. TrAC Trend. Anal. Chem. 2021, 144, 116431. [Google Scholar] [CrossRef]
  3. Sajini, T.; Mathew, B. A brief overview of molecularly imprinted polymers: Highlighting computational design, nano and photo-responsive imprinting. Talanta Open 2021, 4, 100072. [Google Scholar] [CrossRef]
  4. Liu, Z.; Xu, Z.; Wang, D.; Yang, Y.; Duan, Y.; Ma, L.; Lin, T.; Liu, H. A Review on Molecularly Imprinted Polymers Preparation by Computational Simulation-Aided Methods. Polymers 2021, 13, 2657. [Google Scholar] [CrossRef]
  5. Önal Acet, B.; İnanan, T.; Salieva, K.; Borkoev, B.; Odabasi, M.; Acet, Ö. Molecular imprinted polymers: Important advances in biochemistry, biomedical and biotechnology. Polym. Bull. 2024, 81, 10439–10459. [Google Scholar] [CrossRef]
  6. Gkika, D.A.; Tolkou, A.K.; Lambropoulou, D.A.; Bikiaris, D.N.; Kokkinos, P.; Kalavrouziotis, K.; Kyzas, Z. Application of molecularly imprinted polymers (MIPs) as environmental separation tools. RSC Appl. Polym. 2024, 2, 127–148. [Google Scholar] [CrossRef]
  7. Amarh, F.A.; Kangmennaa, A.; Agorku, E.S.; Voegborlo, R.B. A state-of-the-art review of trends in molecularly imprinted polymers in the clean-up of pesticides in environmental samples. Sustain. Environ. 2024, 10, 2298067. [Google Scholar] [CrossRef]
  8. Yaacob, S.F.F.S.; Uwaibatu, M.; Jamil, R.Z.R.; Zain, N.N.M.; Raoov, M.; Suah, F.B.M. Revie of molecular imprinting polymer: Basic characteristics and removal of phenolic contaminants based on the functionalized cyclodextrin monomer. J. Chem. Technol. Biotechnol. 2022, 98, 312–330. [Google Scholar] [CrossRef]
  9. Fresco-Cala, B.; Batista, A.D.; Cárdenas, S. Molecularly Imprinted Polymer Micro- and Nano-Particles: A Review. Molecules 2020, 25, 4740. [Google Scholar] [CrossRef]
  10. Chen, L.; Wang, X.; Lu, W.; Wu, X.; Li, J. Molecular imprinting: Perspectives and applications. Chem. Soc. Rev. 2016, 45, 2137–2211. [Google Scholar] [CrossRef]
  11. Haupt, K. Peer Reviewed: Molecularly Imprinted Polymers: The Next Generation. Anal. Chem. 2003, 75, 376A–383A. [Google Scholar] [CrossRef] [PubMed]
  12. Cheong, W.J.; Yang, S.H.; Ali, F. Molecular imprinted polymers for separation science: A review or reviews. J. Sep. Sci. 2013, 36, 609–628. [Google Scholar] [CrossRef]
  13. Wan, Q.; Liu, H.; Deng, Z.; Bu, J.; Li, T.; Yang, Y.; Zhong, S. A critical review of molecularly imprinted solid phase extraction technology. J. Polym. Res. 2021, 28, 401. [Google Scholar] [CrossRef]
  14. Crini, G. Review: A History of Cyclodextrins. Chem. Rev. 2014, 114, 10940–10975. [Google Scholar] [CrossRef] [PubMed]
  15. Esteso, M.E.; Romero, C.M. Cyclodextrins: Properties and Applications. Int. J. Mol. Sci. 2024, 25, 4547. [Google Scholar] [CrossRef]
  16. Xiao, Z.; Zhang, Y.; Niu, Y.; Ke, Q.; Kou, X. Cyclodextrins as carriers for volatile aroma compounds: A review. Carbohydr. Polym. 2021, 268, 118292. [Google Scholar] [CrossRef] [PubMed]
  17. Del Valle, E.M.M. Cyclodextrins and their uses: A review. Process Biochem. 2004, 39, 1033–1046. [Google Scholar] [CrossRef]
  18. Arrua, R.D.; Strumia, M.C.; Igarzable, C.I.A. Macroporous Monolithic Polymers: Preparation and Applications. Materials 2009, 2, 2429–2466. [Google Scholar] [CrossRef]
  19. Wu, D.; Xu, F.; Sun, B.; Fu, R.; He, H.; Matyjaszewski, K. Design and Preparation of Porous Polymers. Chem. Rev. 2012, 112, 3959–4015. [Google Scholar] [CrossRef]
  20. Liu, Q.; Xiong, J.; Lin, W.; Liu, J.; Wan, Y.; Guo, C.; Wang, Q.; Liu, Z. Porous polymers: Structure, fabrication and application. Matr. Horiz. 2025. [Google Scholar] [CrossRef]
  21. Bohr, S.J.; Wang, F.; Metze, M.; Vukusic, J.L.; Sapalidis, A.; Ulbricht, M.; Nestier, B.; Barbe, S. State-of-the art review of porous polymer membrane formation characterization-How numerical and experimental approaches dovetail to drive innovation. Front. Sustain. 2023, 4, 1093911. [Google Scholar] [CrossRef]
  22. Mohamed, M.G.; El-Mahdy, A.F.M.; Kotp, M.G.; Kuo, S.W. Advances in porous organic polymers: Syntheses, structures, and diverse applications. Mater. Adv. 2022, 3, 707–733. [Google Scholar] [CrossRef]
  23. Song, W.; Zhang, Y.; Tran, C.H.; Choi, H.K.; Yu, D.G.; Kim, I. Porous organic polymers with defined morphologies: Synthesis, assembly, and emerging applications. Prog. Polym. Sci. 2023, 142, 101691. [Google Scholar] [CrossRef]
  24. Ahmed, D.S.; El-Hiti, G.; Yousif, E.; Ali, A.A.; Hameed, A.S. Design and synthesis of porous polymeric materials and their applications in gas capture and storage: A review. J. Polym. Res. 2018, 25, 75. [Google Scholar] [CrossRef]
  25. Liu, Z.; Ou, J.; Zou, H. Click polymerization for preparation of monolithic columns for liquid chromatography. TrAC-Trend Anal. Chem. 2016, 82, 89–99. [Google Scholar] [CrossRef]
  26. Eeltink, S.; Meston, D.; Svec, F. Recent developments and applications of polymer monolithic stationary phases. Anal. Sci. Adv. 2021, 2, 250–260. [Google Scholar] [CrossRef]
  27. Mansour, F.R.; Waheed, S.; Paull, B.; Maya, F. Porogens and porogen selection in the preparation of porous polymer monoliths. J. Sep. Sci. 2019, 43, 56–69. [Google Scholar] [CrossRef]
  28. Svec, F. Porous polymer monoliths: Amazingly wide variety of techniques enabling their preparation. J. Chromatogr. A 2010, 1217, 902–924. [Google Scholar] [CrossRef]
  29. Cheng, X.; Bae, J. Recent Advancements in Fabrication, Separation, and Purification of Hierarchically Porous Polymer Membranes and Their Applications in Next-Generation Electrochemical Energy Storage Devices. Polymers 2024, 16, 3269. [Google Scholar] [CrossRef]
  30. Liu, W.; Yang, Y.; Guo, L.; Di, J.; Lau, C.H.; Bermeshev, M.V.; Shao, L. Recent advances in porous organic polymers for sustainable gas separation. Chem. Eng. J. 2024, 498, 155569. [Google Scholar] [CrossRef]
  31. Denter, U.; Schollmeyer, E. Surface modification of synthetic and natural fibres by fixation of cyclodextrin derivatives. J. Incl. Phenom. Macrocycl. Chem. 1996, 25, 197–202. [Google Scholar] [CrossRef]
  32. Naga, N.; Takenouchi, T.; Nakano, T. Ring-Opening Polymerization of Triaziridine Compounds in Water: An Extremely Facile Method to Synthesize a Porous Polymer through Polymerization-Induced Phase Separation. ACS Macro. Lett. 2022, 11, 602–607. [Google Scholar] [CrossRef] [PubMed]
  33. Abe, I.; Hayashi, K.; Hirashima, T.; Kitagawa, M. Relationship between the Freundlich adsorption constants K and 1/M for hydrophobic adsorption. J. Am. Chem. Soc. 1982, 104, 6452–6453. [Google Scholar] [CrossRef]
  34. Abe, I.; Hayashi, K.; Hirashima, T.; Kitagawa, M. Adsorption of saccharides from aqueous so1ution onto activated carbon. Carbon. 1983, 21, 189–191. [Google Scholar] [CrossRef]
  35. Kano, F.; Abe, I.; Kayama, H.; Ueda, I. Derivation of Langmuir and Freundlich Adsorption Isotherms. Proc. Instuitte Stat. Math. 1991, 39, 53–61. [Google Scholar]
Separations 12 00094 sch001
Scheme 1. Synthesis of 3AZ-CD porous composites polymers by ring-opening polymerization of 3AZ in the presence of CDs simultaneous phase separation.
Scheme 1. Synthesis of 3AZ-CD porous composites polymers by ring-opening polymerization of 3AZ in the presence of CDs simultaneous phase separation.
Separations 12 00094 sch001
Separations 12 00094 g001
Figure 1. SEM images of 3AZ-CD porous polymer composites (3AZ in feed: 20 wt%, reaction temperature: 20 °C); CD: α-CD, γ-CD, Me-β-CD, or HP-β-CD. The particle size is indicated (average diameter).
Figure 1. SEM images of 3AZ-CD porous polymer composites (3AZ in feed: 20 wt%, reaction temperature: 20 °C); CD: α-CD, γ-CD, Me-β-CD, or HP-β-CD. The particle size is indicated (average diameter).
Separations 12 00094 g001
Separations 12 00094 g002
Figure 2. A model of polymerization-induced phase separation via spinodal decomposition processes.
Figure 2. A model of polymerization-induced phase separation via spinodal decomposition processes.
Separations 12 00094 g002
Separations 12 00094 g003
Figure 3. Stress–strain curves of 3AZ-HP-β-CD porous polymer composites. 3AZ in feed: 20 wt%; reaction temperature: 20 °C. CD concentration in feed: (a) 0 wt% (entry 0), (b) 5 wt% (entry 12), (c) 10 wt% (entry 13), (d) 15 wt% (entry 14), (e) 20 wt% (entry 15).
Figure 3. Stress–strain curves of 3AZ-HP-β-CD porous polymer composites. 3AZ in feed: 20 wt%; reaction temperature: 20 °C. CD concentration in feed: (a) 0 wt% (entry 0), (b) 5 wt% (entry 12), (c) 10 wt% (entry 13), (d) 15 wt% (entry 14), (e) 20 wt% (entry 15).
Separations 12 00094 g003
Separations 12 00094 g004
Figure 4. (i) UV–vis spectra of phph solution. (a) Original and after immersion of 3AZ-HP-β-CD porous polymer composites, 3AZ in feed: 20 wt%, reaction temperature: 20 °C; HP-β-CD content: (b) 0 wt% (entry 0, reference), (c) 11.4 wt% (entry 12), (d) 14.7 wt% (entry 13), (e) 19.3 wt% (entry 14), (f) 26.7 wt% (entry 15). (ii) Adsorption isotherms, Langmuir and Freundlich, for phph adsorption by 3AZ-HP-β-CD porous polymer composites (entry 13).
Figure 4. (i) UV–vis spectra of phph solution. (a) Original and after immersion of 3AZ-HP-β-CD porous polymer composites, 3AZ in feed: 20 wt%, reaction temperature: 20 °C; HP-β-CD content: (b) 0 wt% (entry 0, reference), (c) 11.4 wt% (entry 12), (d) 14.7 wt% (entry 13), (e) 19.3 wt% (entry 14), (f) 26.7 wt% (entry 15). (ii) Adsorption isotherms, Langmuir and Freundlich, for phph adsorption by 3AZ-HP-β-CD porous polymer composites (entry 13).
Separations 12 00094 g004
Separations 12 00094 g005
Figure 5. A plausible model of phph adsorption by 3AZ-Me-β-CD and HP-β-CD porous polymer composites.
Figure 5. A plausible model of phph adsorption by 3AZ-Me-β-CD and HP-β-CD porous polymer composites.
Separations 12 00094 g005
Table 1. Composition, structure, and mechanical properties of 3AZ-CD porous polymer composites (3AZ in feed: 20 wt%, reaction temperature: 20 °C).
Table 1. Composition, structure, and mechanical properties of 3AZ-CD porous polymer composites (3AZ in feed: 20 wt%, reaction temperature: 20 °C).
EntryCDCD in Feed
wt%		CD in Composite
1wt%		Average Diameter
μm		Bulk Density
g/cm3		Porosity
%		Young’s Modulus
kPa
0non 04.580.26775.71150
1α-CD 5.012.73.700.32970.81657
2α-CD10.018.23.340.33070.91861
3α-CD15.020.0n.d. 20.35968.41974
4α-CD20.021.8n.d. 20.43262.13809
5γ-CD 5.0 9.74.260.33470.12790
6γ-CD10.012.03.880.34569.23284
7γ-CD15.020.53.280.36667.65192
8γ-CD20.030.02.880.38566.18800
9Me-β-CD 5.0 9.73.800.31172.42560
10Me-β-CD10.015.73.430.31172.63250
11Me-β-CD15.023.23.240.34470.13902
12HP-β-CD 5.011.44.000.34070.11342
13HP-β-CD10.014.73.710.34470.02160
14HP-β-CD15.019.33.100.34770.15679
15HP-β-CD20.026.72.810.36868.75950
1 Calculated using Equation (3). 2 Not determined (n.d.) due to their distorted structures.
Table 2. Adsorption test of phph by 3AZ-Me-β-CD and HP-β-CD porous polymer composites, 3AZ in feed: 20 wt%, reaction temperature: 20 °C.
Table 2. Adsorption test of phph by 3AZ-Me-β-CD and HP-β-CD porous polymer composites, 3AZ in feed: 20 wt%, reaction temperature: 20 °C.
RunCDCD Content
wt%		qe 1
mg/g
9Me-β-CD9.7104.9
10Me-β-CD15.7483.5
11Me-β-CD23.2624.1
12HP-β-CD11.4247.3
13HP-β-CD14.7542.5
14HP-β-CD19.3624.5
15HP-β-CD26.7579.7
1 Adsorption value of phph per unit weight of the porous polymer composite calculated using Equation (2).
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Naga, N.; Miyazaki, Y.; Nakano, T. Porous Composite Polymers Composed of Polyethyleneimine and Cyclodextrins: Synthesis and Application as Adsorbents for an Organic Compound. Separations 2025, 12, 94. https://doi.org/10.3390/separations12040094

AMA Style

Naga N, Miyazaki Y, Nakano T. Porous Composite Polymers Composed of Polyethyleneimine and Cyclodextrins: Synthesis and Application as Adsorbents for an Organic Compound. Separations. 2025; 12(4):94. https://doi.org/10.3390/separations12040094

Chicago/Turabian Style

Naga, Naofumi, Yuma Miyazaki, and Tamaki Nakano. 2025. "Porous Composite Polymers Composed of Polyethyleneimine and Cyclodextrins: Synthesis and Application as Adsorbents for an Organic Compound" Separations 12, no. 4: 94. https://doi.org/10.3390/separations12040094

APA Style

Naga, N., Miyazaki, Y., & Nakano, T. (2025). Porous Composite Polymers Composed of Polyethyleneimine and Cyclodextrins: Synthesis and Application as Adsorbents for an Organic Compound. Separations, 12(4), 94. https://doi.org/10.3390/separations12040094

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop