Semi-Natural Superabsorbents Based on Starch-g-poly(acrylic acid): Modification, Synthesis and Application (original) (raw)
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Defect and Diffusion Forum, 2009
A series of biodegradable superabsorbent polymers (SAP) based on starch grafted with acrylic acid (AA) and crosslinked with N,N'-methylenebisacrylamide (MBIS) were obtained. The parameters that define SAPs properties, such as starch type, amount of initiator, acrylic acid and crosslinker concentrations, and degree of neutralization were varied according to an experimental design. The swelling rate, the degree of swelling, the water sorption isotherms and the texture profile of the new materials were determined. A new method was used to measure the swelling rate. The water sorption results were correlated using various isothermal models as the BET (Brunauer-Emmett-Teller) and GAB (Guggenheim-Andersson-DeBoer) models.
Biodegradation studies of starch based composite superabsorbents
Polymers & polymer composites, 2004
The potential of a new starch based composite consisting of acrylamide, a crosslinking agent, N, N'methylene-bis-acrylamide and sand(white quartz) to act as a superabsorbent polymer was investigated. The modification of starch by grafting with acrylamide induced ...
Carbohydrate Polymers, 2006
Biodegradable superabsorbent polymers were synthesized by graft copolymerization of acrylamide (AM)/itaconic acid (IA) onto cassava starch via a redox initiator system of ammonium persulfate (APS) and N,N,N 0 ,N 0 -tetramethylethylenediamine (TEMED), in the presence of N,N 0 -methylenebisacrylamide (N-MBA) crosslinking agent, sodium bicarbonate foaming agent, a triblock copolymer of polyoxyethylene/polyoxypropylene/polyoxyethylene as a foam stabilizer. The acrylamide-to-itaconic acid ratio, the starch-to-monomer ratio, and concentrations of the crosslinking agent and initiator, on the water absorption of the superabsorbent polymers were investigated. The swelling of starch-g-PAM was 39 g g À1 while the starch-g-P(AM-co-IA) with the IA content of 0.02-0.15% mole gave the water swelling value in the range of 70-390 g g À1 . By-products of the reaction were removed by water extraction. The starch grafted composites were characterized by FTIR and SEM. Thermal gravimetric analysis was also used for determining the percentage of grafting ratio. Biodegradation of the starch grafted copolymer was carried out using a-amylase. After the a-amylase hydrolysis, the amount of reducing sugar was quantified by DNS method. The hydrolyzed solution gave a negative test with iodine solution and a positive test by Benedict's solution, an indication of the existence of glucose units.
Utilization of Cassava Starch in Copolymerisation of Superabsorbent Polymer Composite (SAPC)
Journal of Engineering and Technological Sciences, 2014
Cassava starch was used as the main chain in the copolymerization of a superabsorbent polymer composite (SAPC) based on acrylic acid and bentonite. The SAPC was synthesized through graft polymerization using nanosized bentonite as reinforcement. The variables in this experiment were: bentonite concentration, acrylic acid to starch weight ratio, concentration of initiator, and cross linker. The product was characterized using FTIR, SEM and TGA-DSC. The results show that the polymerization reactions involved processes of incorporating starch chains as polymer backbone and grafting acrylic acid monomers onto it. The use of cassava starch in the polymerisation produced a very short reaction time (10-15 minutes), which led to SAPC production with higher efficiency and lower cost. Bentonite interacts with monomers via hydrogen and weak bonding, thus improving the thermal properties of the product. The maximum absorbance capacity obtained was at an acrylic acid to starch weight ratio of 5 and a concentration of initiator, cross linker and bentonite of 0.5, 0.05 and 2 weight percent, respectively. The product is suitable for agricultural and medical applications as well as common superabsorbent polymer applications.
Journal of Polymers and the Environment, 2019
During the past decades, production and applications of petroleum-based superabsorbents have grown dramatically; currently, superabsorbents are produced from acrylic acid, which consequently increase the environmental concerns. The high consumption rate of superabsorbent on the one hand, and their persistence in the environment from the other hand would make the waste of this material a potential hazard for the environment. These materials are not biodegradable, and if degraded hazardous derivatives would be released into soil and water. The current work presents the synthesis and the performance of a novel superabsorbent hydrogel, based on star-shaped bio-based compartments and acrylic acid. Herein, the synthesis of two bio-based star-shaped monomers will be reported based on the condensation reaction between hydroxyl and carboxylic acid end groups of a bio-acid and a bio-alcohol. The first monomer was synthesized from glycerin, succinic acid, lactic acid, itaconic acid, and acrylic acid. The second monomer was synthesized from glycerin, lactic acid, and methacrylic acid. The monomers structures were characterized via FT-IR and 1 HNMR spectroscopies. The different portions of biobased monomers (10, 30, 50, and 70 wt%) were used in combination with the acrylic acid monomer to form hybrid superabsorbents. The swelling properties and the absorbency under load (AUL) of superabsorbents were investigated in turn. The maximum absorption capacities (398.49 and 90.10 g g −1 in water and saline solution, respectively) were observed when 30 wt% of acrylic acid backbone of the superabsorbent was replaced with the bio-based monomer. Moreover, economic and environmental profiles of the hybrid SAPs have been evaluated. The comparative environmental assessment performed using life cycle analysis method, based on the material and energy balances obtained from the available literature. While the economy of the hybrid SAPs production still suffers from the high price of the employed raw biomaterials during manufacturing, the better environmental profiles obtained for the hybrid SAPs.
Polymers and Polymer Composites
Superabsorbent polymers (SAPs) were synthesized by aqueous solution polymerization of carboxymethyl cellulose (CMC)/acrylic acid (AAc) and polyvinyl alcohol (PVA)/AAc blend using benzoyl peroxide as an initiator. SAPs were synthesized by a facile method under mild conditions. A comparative study was done between CMC/AAc as a biodegradable superabsorbent and PVA/AAc copolymer. The effects of cross-linking, reaction time, temperature, and initiator molar ratio on water absorbency were studied herein. The highest swelling capacity was obtained for CMC/AAc biodegradable superabsorbent composite. The water absorption capacity of SAPs increased with increases in benzoyl peroxide content, immersion time, and reaction temperature of polymerization. The gel fraction of SAPs decreased with increases in the amounts of N, N′-methylenebisacrylamide as a cross-linker. Fourier-transform infrared spectroscopy was used to examine the molecular interactions. The morphology and structure of superabsor...
New routes to prepare superabsorbent polymers free of acrylate cross-linker
Iranian Polymer Journal, 2015
Absorbent properties of the prepared superabsorbent polymers were evaluated in saline solution and results showed high dependency of the absorbent properties on the crosslinking agent polarity and concentration. Superabsorbent polymers cross-linked with EAS and GDGE showed the highest absorbency under loading and indicated that they formed gels with high strength in the aqueous solution. Absorbent properties of the prepared SAPs showed reversible correlation with cross-linking agent concentration. The pH of the reaction mixture was optimized to achieve the highest free swell and absorbency under loading. The biodegradation properties of the superabsorbent polymers cross-linked with sucrose-based cross-linking agents were also evaluated and they showed degradation behavior under the influence of organisms Pseudomonas aeruginosa and Trichophyton rubrum.
Effect of Cross-linking on Grafting and Superabsorbency of Acryloylated Starch
Chemical modification of starch was carried out using epichlorohydrin as cross-linking agent; the cross-linked potato starch was acryloylated before grafting with acrylic acid (AA) using Fenton's reagent as initiator. Characterization of the cross-linked acryloylated starch was carried out with FTIR, TGA and SEM analyses. The carbonyl stretching bond at 1711 cm-1 and change in temperature of maximum decomposition from 282˚C to 200˚C in the starch and the cross-linked starch ester respectively, have confirmed successful acryloylation. The optimum temperature of the reaction was found to be 60 °C, while the optimum starch to acrylic acid ratio was 1:3. The number of acryloyl groups per starch molecule and degree of neutralisation determined the superabsorbent behaviour of the samples; the DS of 0.8 and 75 % neutralisation were discovered to yield a polymer sample with the highest absorbency in this experiment. Under all the experimental conditions studied, a polymer with improved grafting percentage, ratio, efficiency and low amount of homopolymer with excellent water retention ability and remarkable absorbency under load was obtained.
International Journal of Plastics Technology, 2019
A novel superabsorbent polymer composite based on mung bean starch was prepared via emulsion polymerization technique of partially neutralized acrylic acid grafted onto waste polystyrene chain using ammonium persulfate and N,N′methylenebisacrylamide as initiator and crosslinker, respectively. Fourier transform infrared confirmed the presence of mung bean starch in the grafting of polyacrylic acid and waste polystyrene. The introduction of starch in superabsorbent polymer greatly enhanced the swelling capacity with the optimum absorbency recorded at 59.3 g/g for 20% of starch loading. Meanwhile, thermogravimetric analysis showed enhance in thermal stability upon incorporation of mung bean starch.
European Polymer Journal, 2019
The current review provides an overview of different types of superabsorbent polymers (SAPs) together with appropriate strategies elaborated to enable their synthesis. The main focus will be on polysaccharide-based, semi-synthetic and 'smart' SAPs along with their derivatives. SAPs have already shown their use in a plethora of applications including diapers, the biomedical field, agriculture, etc. The different polymer classification possibilities are discussed, as well as the classification of the constituting building blocks. The main part of SAPs still has a synthetic origin. However, as they are often not biocompatible, biodegradable or renewable, natural SAPs based on polysaccharides have gained increasing interest. Due to the low solubility of synthetic polymers, purification problems or the need for organic solvents, a trend has emerged towards combining polysaccharides with synthetic monomers to create semi-synthetic, hybrid SAPs for specialized applications with fine-tuned properties including wound dressings, fertilizers or self-healing concrete. These specialized, semi-synthetic SAPs offer strong potential for a series of applications in the future. However, future research in this respect is still needed to optimize homogeneity and to increase gel fractions. A final part of this review includes 'smart' SAPs such as SAPs with a T-, electro-and pH-sensitivity. These 'smart' SAPs are especially becoming useful for certain biomedical applications such as drug release for which an in vivo location can be targeted. The use of 'smart', semi-synthetic SAPs with fine-tuned characteristics combining the best characteristics of both synthetic and natural SAPs, offer the greatest potential for the future.