Preparation, Swelling and Water-Retention Properties of Crosslinked Superabsorbent Hydrogels Based on Guar Gum

2010 ◽  
Vol 96 ◽  
pp. 177-182 ◽  
Author(s):  
Wen Bo Wang ◽  
Ai Qin Wang
Keyword(s):  
Acrylic Acid ◽  
Water Retention ◽  
Guar Gum ◽  
Weight Ratio ◽  
Ammonium Persulfate ◽  
Sodium Acrylate ◽  
Swelling Properties ◽  
Superabsorbent Hydrogel ◽  
Water Retention Properties ◽  
Superabsorbent Hydrogels

Utilization of natural polymer as matrix for preparing hydrogels can improve the performance of the materials and render them environmentally friendly. In this work, the guar gum-g-poly(sodium acrylate) (GG-g-PNaA) superabsorbent hydrogels were prepared by the solution graft copolymerization of natural guar gum (GG) with partially neutralized acrylic acid (NaA) using ammonium persulfate (APS) as initiator and N,N′-methylenebisacrylamide (MBA) as crosslinker. FTIR spectra confirmed that NaA had been grafted on GG chains. The effects of reaction variables including the concentration of APS and MBA, the weight ratio of acrylic acid (AA) to GG and the neutralization degree of AA on water absorption were investigated. The superabsorbent hydrogel prepared under optimal condition gives the best absorption of 1107 g∙g–1 in distilled water and 88 g∙g–1 in 0.9 wt% NaCl solution. Effects of external pH on the swelling properties of hydrogels were investigated, and the practical water retention properties of the hydrogels were also evaluated. Results indicated that the hydrogels exhibited excellent pH-stability in a wide pH range from 4 to 11, and the water-retention capabilities of sand soils were also greatly improved after utilizing the superabsorbent hydrogels. This superabsorbent hydrogels could be used as potential eco-friendly water-saving materials for agricultural or ecological application.

Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Ali Pourjavadi ◽  
Mohammad Sadeghi ◽  
Mohammad Mahmodi Hashemi ◽  
Hossein Hosseinzadeh
Keyword(s):  
Weight Ratio ◽  
Ammonium Persulfate ◽  
Switching Behavior ◽  
Polymerization Reaction ◽  
Sodium Acrylate ◽  
Swelling Kinetics ◽  
Superabsorbent Hydrogel ◽  
Swelling Capacity ◽  
Bioactive Agents ◽  
Kinetics Of

AbstractIn this article, we synthesize a novel gelatin-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto gelatin backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. The effect of grafting variables, i.e. concentration of MBA and APS, AA/AAm weight ratio, and reaction time and temperature, was systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling behavior of these absorbent polymers was also investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 7.0. This on-off switching behavior makes the synthesized hydrogels an excellent candidate for controlled delivery of bioactive agents. Finally, the swelling kinetics of the synthesized hydrogels with various particle sizes was preliminarily investigated.

Synthesis and Water Retention Properties of Poly(Acrylamide)-g-Kenaf Fiber Hydrogel

2015 ◽  
Vol 1119 ◽  
pp. 310-313
Author(s):  
Ila Najaa Ali Badaruddin ◽  
Shahrir Hashim
Keyword(s):  
Water Retention ◽  
Ammonium Persulfate ◽  
Solution Polymerization ◽  
Agricultural Field ◽  
Kenaf Fiber ◽  
Superabsorbent Hydrogel ◽  
Liquid Fertilizer ◽  
Urea Fertilizer ◽  
Water Retention Properties ◽  
Poly Acrylamide

The purpose of this research was to study water retention properties of superabsorbent hydrogel based on poly (acrylamide)/biofiller hydrogel and urea liquid fertilizer, by solution polymerization. Kenaf fiber (KF) was used as biofiller and the preparation of the poly (acrylamide)-grafted-kenaf fiber (PAAm-g-KF) hydrogel was carried out by polymerizing the monomer. Urea fertilizer was employed as polymerization media. N,N’-methylene bisacrylamide (MBA) was used as a crosslinker and ammonium persulfate (APS) as an initiator. Water retention of the hydrogel was studies in soil with three different samples (Controlled, PAAm Hydrogel, PAAm-g-KF). The PAAm-g-KF was also applied to agricultural field. The results show that PAAm-g-KF greatly improved water retention in the soil and agricultural field.

The Preparation of Calcium Carbonate Modified High Water-Absorbing Resin

2014 ◽  
Vol 1035 ◽  
pp. 296-302
Author(s):  
Qi Shi ◽  
Qing Luo Meng ◽  
Nong Wang
Keyword(s):  
Calcium Carbonate ◽  
Acrylic Acid ◽  
Dry Weight ◽  
High Water ◽  
Ammonium Persulfate ◽  
Sodium Acrylate ◽  
Cross Linking ◽  
Optimum Process ◽  
Process Conditions ◽  
Modified Resin

The poly (sodium acrylate/acrylic acid) water-absorbing resin was prepared by aqueous solution polymerization with acrylic acid (AA) as the monomer, calcium carbonate as the modified additives, N, N-methylene double acrylamide (NMBA) as cross-linking agent, ammonium persulfate (APS)/sodium sulfite oxidation reduction type initiator. It was found that the adsorption performance of absorbent resin modified by calcium carbonate strengthened obviously. Orthogonal and single factor experiment were used to establish the optimum parameters related to the product preparation. The best process conditions on water-absorbing properties of the modified resin was obtained. Using 150mL acrylic acid as a benchmark, the result show the optimum process conditions: the reaction temperature is 55°C, the mass fraction of monomer is 20%, the neutralization degree is 45%, modified additive dosage is 10 g, the dosage of cross-linking agent is 0.1%, and the initiator dosage is 2.0%, respectively. After made under the optimum process conditions, the water-absorbing rate of the modified resin was 676.6 times the dry weight.

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