Modifying acrylic‐based superabsorbents. II. Modification of process nature

Omidian, Hossein; Hashemi, Seyed Ali; Askari, Fahimeh; Nafisi, S.

doi:10.1002/app.1994.070540211

Cited by 27 publications

(24 citation statements)

References 1 publication

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“…Details about deriving structural parameters were reported elsewhere. 3 The sample A1 (with no crosslinking agent) is water-soluble. As clearly shown in Figure 1, by increasing the network chain density ( i.e., increasing the amount of the crosslinker used), the amount of equilibrium swelling decreases.…”

Section: Resultsmentioning

confidence: 99%

Modifying acrylic‐based superabsorbents. I. Modification of crosslinker and comonomer nature

Omidian

Hashemi

Askari

et al. 1994

J of Applied Polymer Sci

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SYNOPSISThis article is devoted to the synthesis, characterization, and modification of acrylic-based superabsorbents which are synthesized by carrying out the well-known process of inverse suspension polymerization. The dispersion is stabilized by using a mixture of micromolecular and macromolecular stabilizers. High swelling and appropriate absorption kinetics are obtained, provided that parameters (including initial monomer and crosslinker concentration, range of neutralization degree, initiating and stabilizing system, monomer addition rate, temperature and nature of the organic phase) are being considered. Modifications of crosslinker and comonomer nature and their effects on absorbency characteristics (capacity and rate) of the above-mentioned superabsorbents are graphically presented. Finally, diffusion behavior of superabsorbents is briefly discussed.

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Section: Resultsmentioning

confidence: 99%

Modifying acrylic‐based superabsorbents. I. Modification of crosslinker and comonomer nature

Omidian

Hashemi

Askari

et al. 1994

J of Applied Polymer Sci

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“…The lower values of the swelling capacity of copolySAP might be attributed to the increase number of cross-links per polymer chain which relatively results in a strong molecular structure. Consequently, when the crosslinking density increases, the swelling capacity will decrease [7][8][9][21][22][23]. However it is interesting to note that the swelling capacity decreases faster in case of Poly-SAP samples, see regression lines slopes in the Figure 1.…”

Section: Synthesis Of Copolymer Sap (Copolysap)mentioning

confidence: 99%

“…As polymer (SAP) is immersed in water, random coils of polymer become more aligned on swelling which reduces the entropy of the chains. There is a direct relationship between cross-link density and polymer characteristics, as increase in cross-link density decrease swelling capacity and increase gel strength of the polymer [7][8][9] SAPs can be synthesized using either solution [10] or inverse suspension/emulsion polymerization [11,12] techniques. Both of the polymerization techniques have their own advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Superabsorbent Polymer (SAP) via Industrially Preferred Route

Rafiq

Syed

2016

J. Basic Appl. Sci.

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The assigned study is dedicated to the synthesis, improvement and characterization of acrylic-based superabsorbent polymers (SAPs) which can be used in versatile applications notably in disposable diapers and pharmaceutics. The industrially preferred solution polymerization route and low cost monomers were used to synthesize SAPs. Homopolymer and copolymer based SAPs were prepared with varying amount of cross-linker and initiator concentrations and compared for swelling rate with a commercially available SAP sample. Swelling capacity linearly decreases with increase in cross-linker content for both the synthesized SAPs samples whereas it first increases and then decreases with initiator content for the synthesized copolymer SAP. Swelling kinetics of the synthesized and commercial SAPs were modelled using model equation proposed by Omidian et al. Both the synthesized SAPs showed substantial increase in swelling capacity whereas copolymer SAP exhibited the highest swelling rate (rate parameter 2.78 min) when compared to homopolymer SAP and the commercially available SAP samples. Accordingly, the copolymer SAP may find its application in disposable diapers or pharmaceutics where the higher swelling rate is of prime importance. Copolymer and commercially available SAPs depicted significant decrease in swelling capacity even at very low saline solution concentration (0.01 %).

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“…Apparently the inverse emulsion polymerization initiated by water soluble initiators is a solution polymerization in the microparticles [5,6] while when the oil soluble initiator is used the micellar model is valid in some cases. [7] It has been reported in literature [8] that the swelling rate of a superabsorbent prepared by suspension process is twelve times faster than prepared by solution process. Studies have also revealed that increasing amount of crosslinker reduced the ultimate swelling capacity but speeded up the rate of swelling for products made by both processes.…”

Section: Introductionmentioning

confidence: 99%

Inverse Suspension Polymerization of Partially Neutralized and Lightly Cross‐Linked Acrylic Acid: Effect of Reaction Parameters

Choudhary

2009

Macromolecular Symposia

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An inverse suspension polymerization was carried out in laboratory in one Liter Buchi glass reactor to produce superabsorbent polymers (SAPs) based on acrylic monomers for hygiene applications. Strongly water absorbing polymers, based on acrylic acid, sodium acrylate were prepared by copolymerization using potassium per sulfate as initiator and N-N 0 methylene-bisacrylamide (MBA) as crosslinking agent. The effect of varying monomer, crosslinker, initiator, dispersant concentration, time of reaction and degree of neutralization, on absorption capacities was investigated. In the present studies, the continuous hydrocarbon phase was taken as 50:50 mixture of n-heptane and cyclohexane (aliphatic-alicyclic) because the availability of crosslinker in the aqueous phase is controlled by the partition coefficient of the crosslinker between the aqueous phase and the continuous hydrocarbon phase. The SAPs were evaluated for their free absorption capacities in distilled water, saline (0.9% NaCl), and also absorption under load (AUL). The experimental results show that these SAPs have good absorbency both in water and NaCl solutions. It was observed that SAP synthesized from acrylic acid with about 70% degree of neutralization, containing 1% cross-linker, and 0.5-1.0% initiator concentration with 10% dispersant exhibited absorption capacities in water, saline and AUL as 220 g/g, 70 g/g and 27 g/g respectively.

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Modifying acrylic‐based superabsorbents. II. Modification of process nature

Cited by 27 publications

References 1 publication

Modifying acrylic‐based superabsorbents. I. Modification of crosslinker and comonomer nature

Modifying acrylic‐based superabsorbents. I. Modification of crosslinker and comonomer nature

Synthesis of Superabsorbent Polymer (SAP) via Industrially Preferred Route

Inverse Suspension Polymerization of Partially Neutralized and Lightly Cross‐Linked Acrylic Acid: Effect of Reaction Parameters

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