Photoinduced surface crosslinking of superabsorbent polymer particles

Jockusch, Steffen; Turro, Nicholas J.; Mitsukami, Yoshiro; Matsumoto, Makoto; Iwamura, Taku; Lindner, Torsten; Flohr, Andreas; Massimo, Giuseppe di

doi:10.1002/app.29209

Cited by 43 publications

(39 citation statements)

References 21 publications

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“…The surface-cross-linked particles maintain their shape during the swelling process, which generates a less densely packed gel bed with air pockets, so the fluid can flow in a less restricted fashion (Figure 1, b). This higher permeability allows for a more efficient use of the gel bed [10]. [10] …”

Section: Surface Crosslinkingmentioning

confidence: 99%

Proposed Cross-Linking Model for Carboxymethyl Cellulose /Starch Superabsorbent Polymer Blend

Braihi¹

2014

IJMSA

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Superabsorbent polymer (SAP) blend has been synthesized from Carboxymethyl Cellulose (CMC) , starch, and aluminum sulfate octadecahydrate cross-linker. Water Absorption Capacity (WAC), FTIR, SEM, DSC, CHO, Flame Photometer and ignition tests are carried out to determine the used CMC formula, investigate the cross-linking process, and suggest a cross-linking model. Flame Photometer results showed there are two sodium acetate groups in the CMC molecule. This result confirmed by theoretical calculations and CHO test . To investigate which of Al 3+ and SO 4 2-ions causes the crosslinking : the extraction of the cross-linked CMC/starch tested with BaCl 2 solution(showed dense white precipitate ; sulfate group not share for blend formation), NaOH solution( showed white precipitate of aluminum hydroxide; Al 3+ ion present (i.e. Al 3+ ion share in the blend structure). These results confirmed by flame test for sodium ion, which showed high Na emission energy (5.75); there is an exchange between Al and Na ions. To check that aluminum is a part of the structure, sample of the cross-linked CMC ignited. A white precipitate appear for aluminum oxide ,which confirms the presence of Al. Based on that there are three CMC molecules connected to each Al atom, theoretical calculations about the amount of Al in the cross-linked CMC molecule showed a good agreement with the CHO results (5.613% Vs. 5.739 % respectively). FTIR spectrum of the cross-linked CMC/starch blend showed that there is a reaction between CMC and starch molecules; i.e. the new repeating unit contains three starch molecules. This conclusion confirmed by theoretical calculations and results of EDX, CHO, and ignition tests. Al% in the new mer appeared a good agreement between theoretical calculations (4.32%) and CHO results (4.512%). Ignition test calculations confirmed that the new mer contains three Al atoms. Evidences of the occurrence of the cross-linking process were obtained from FTIR, morphology, DSC and absorbency results. Absence of the primary hydroxyl alcohol band in the CMC/starch blend spectrum, indicates that this site is active and the reaction between starch and CMC molecules occurs through it. Morphologies studies showed that the sample after crosslinking is more compact than before as well as show one piece for after cross-linking comparing with different pieces before cross-linking.Optimum cross-linking ratio appeared to be 2wt% corresponded to WAC equal to 58 g/g.in distilled water and DSC results indicates that CMC/starch is a miscible blend.

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Section: Surface Crosslinkingmentioning

confidence: 99%

Proposed Cross-Linking Model for Carboxymethyl Cellulose /Starch Superabsorbent Polymer Blend

Braihi¹

2014

IJMSA

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“…However, the presented data is only for the polymers with lower CRC (CRC < 30 g/g), and the combined properties (CRC, AUL, and Permeability) of these polymers are still lower than the one produced with a thermally reactive coating. 3 Base polymer produced with free radical solution polymerization has lower AUL (AUL < 10 g/g) and higher CRC than that produced via microwave-assisted polymerization, and a long surface crosslinking step has to be implemented to strengthen the polymer. An alternative approach for improving the properties could be done by employing a base polymer with higher AUL, and therefore shortening the time that it takes to do the surface crosslinking step.…”

Section: Introductionmentioning

confidence: 99%

“…3 This step has been used to improve polymers' absorbency under load, 2 among other properties. It strengthens the base polymer by creating a shell around the core, but the trade-off is its decreased absorption capacity.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, since polyacrylic acid is a water-soluble polymer, a crosslinker is needed to make it water insoluble. Superabsorbent polymer absorbs hundreds of times of its own weight in deionized water, 2,3 its capacity is in the range of 30-50 g/g for 0.9% sodium chloride (used to simulate urine in laboratories). 2 The first generation of superabsorbent polymer in the hygiene industries were base polymers.…”

Section: Introductionmentioning

confidence: 99%

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Microwave‐assisted polymerization: Inert addition and surface coating of superabsorbent polymer for improved physical properties

Azad

Sandros

2016

J of Applied Polymer Sci

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Two different polymerization techniques, microwave-assisted polymerization and free radical solution polymerization, were utilized in the syntheses of superabsorbent polymers with varying amounts of acrylic acid (31-50%). Degrees of neutralization were in the range of 68-80 mol %, and clay level was varied between 0 and 5%. The base polymer produced with microwave-assisted polymerization had higher absorbency under low load (0.3 psi) than those with the free radical solution polymerization. To improve its absorbency under higher loads (0.6 and 0.9 psi), the surface coating step was implemented by using ethylene glycol diglycidyl ether as a surface crosslinking agent. Properties such as capacity, permeability, and absorbency under different loads were tested in 0.9% sodium chloride solution for the base and the surface-coated polymers. In addition, extractables and residual acrylic acid were measured to determine the reaction's efficiency. In conclusion, surface coating improved polymer properties, and the incorporation of clay imparted permeability to the polymer.

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“…Recently, Jockusch et al attempted to eliminate these disadvantages throu-gh a photochemical surface crosslinking method, by UV irradiation with ammonium persulfate as a photoactivated crosslinking agent. 22 This method operates at room temperature, requires shorter reaction times, and generates superior superabsorbent particles. However, the amount of the added solution just wetted the surface of the particles but did not cause significant swelling of the particles.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of Partially Hydrolyzed Acrylonitrile-co-Acrylamide Superabsorbent Hydrogel

Pourjavadi¹,

Hosseinzadeh²

2010

Bulletin of the Korean Chemical Society

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In this work, a novel method to synthesis of an acrylic superabsorbent hydrogel was reported. In the two stage hydrogel synthesis, first copolymerization reaction of acrylonitrile (AN) and acrylamide (AM) monomers using ammonium persulfate (APS) as a free radical initiator was performed. In the second stage, the resulted copolymer was hydrolyzed to produce carboxamide and carboxylate groups followed by in situ crosslinking of the polyacrylonitrile chains. The results from FTIR spectroscopy and the dark red-yellow color change show that the copolymerization, alkaline hydrolysis and crosslinking reactions have been do take place. Scanning electron microscopy (SEM) verifies that the synthesized hydrogels have a porous structure. The results of Brunauer-Emmett-Teller (BET) analysis showed that the average pore diameter of the synthesized hydrogel was 13.9 nm. The synthetic parameters affecting on swelling capacity of the hydrogel, such as AM/AN weight ratio and hydrolysis time and temperature, were systematically optimized to achieve maximum swelling capacity (330 g/g). The swollen gel strength of the synthesized hydrogels was evaluated via viscoelastic measurements. The results indicated that superabsorbent polymers with high water absorbency were accompanied by low gel strength. The swelling of superabsorbent hydrogels was also measured in various solutions with pH values ranging from 1 to 13. Also, the pH reversibility and on-off switching behavior makes the hydrogel as a good candidate for controlled delivery of bioactive agents. Finally, the swelling of synthesized hydrogels with various particle sizes obey second order kinetics.

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Photoinduced surface crosslinking of superabsorbent polymer particles

Cited by 43 publications

References 21 publications

Proposed Cross-Linking Model for Carboxymethyl Cellulose /Starch Superabsorbent Polymer Blend

Proposed Cross-Linking Model for Carboxymethyl Cellulose /Starch Superabsorbent Polymer Blend

Microwave‐assisted polymerization: Inert addition and surface coating of superabsorbent polymer for improved physical properties

Synthesis and Properties of Partially Hydrolyzed Acrylonitrile-co-Acrylamide Superabsorbent Hydrogel

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