The advantageous aspect of using SAP is that it is:
History[ edit ] Until the s, water absorbing materials were cellulosic or fiber-based products. Choices were tissue papercotton, sponge, and fluff pulp. The water absorbent capacity of these types of materials is only up to 11 times their weight and most of it is lost under moderate pressure.
They developed a resin based on the grafting of acrylonitrile polymer onto the backbone of starch molecules i. The hydrolyzed product of the hydrolysis of this starch-acrylonitrile co-polymer gave water absorption greater than times its weight.
Also, the gel did not release liquid water the way that fiber-based absorbents do. A wide range of grafting combinations were attempted including work with acrylic acidacrylamide and polyvinyl alcohol PVA.
Uses include agricultural and horticultural.
This polymer is the most common type of SAP made in the world today. Other materials are also used to make a superabsorbent polymer, such as polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulosepolyvinyl alcohol copolymers, cross-linked polyethylene oxideand starch grafted copolymer of polyacrylonitrile to name a few.
The latter is one of the oldest SAP forms created. Today superabsorbent polymers are made using one of three primary methods: Each of the processes have their respective advantages but all yield a consistent quality of product.
Gel polymerization[ edit ] A mixture of acrylic acid, water, cross-linking agents and UV initiator chemicals are blended and placed either on a moving belt or in large tubs. The liquid mixture then goes into a "reactor" which is a long chamber with a series of strong UV lights. The UV radiation drives the polymerization and cross-linking reactions.
The logs are shredded or ground and placed in various sorts of driers. Additional cross-linking agent may be sprayed on the particles' surface; this "surface cross-linking" increases the product's ability to swell under pressure—a property measured as Absorbency Under Load AUL or Absorbency Against Pressure AAP.
The dried polymer particles are then screened for proper particle size distribution and packaging. The gel polymerization GP method is currently the most popular method for making the sodium polyacrylate superabsorbent polymers now used in baby diapers and other disposable hygienic articles.
Solutions can be diluted with water prior to application, and can coat most substrates or used to saturate them. After drying at a specific temperature for a specific time, the result is a coated substrate with superabsorbency.
For example, this chemistry can be applied directly onto wires and cables, though it is especially optimized for use on components such as rolled goods or sheeted substrates. Solution-based polymerization is commonly used today for SAP manufacture of co-polymers, particularly those with the toxic acrylamide monomer.
This process is efficient and generally has a lower capital cost base. The solution process uses a water-based monomer solution to produce a mass of reactant polymerized gel. The polymerization's own exothermic reaction energy is used to drive much of the process, helping reduce manufacturing cost.
The reactant polymer gel is then chopped, dried and ground to its final granule size.
Any treatments to enhance performance characteristics of the SAP are usually accomplished after the final granule size is created.
Suspension polymerization[ edit ] The suspension process is practiced by only a few companies because it requires a higher degree of production control and product engineering during the polymerization step.
This process suspends the water-based reactant in a hydrocarbon-based solvent.
The net result is that the suspension polymerization creates the primary polymer particle in the reactor rather than mechanically in post-reaction stages. Performance enhancements can also be made during, or just after, the reaction stage.
Artificial snow for motion picture and stage productions  Candles.KEYWORDS: Super absorbent polymers, Jalshakti, adsorption kinetics, Methylene Blue dye, intraparticle diffusion. 1. INTRODUCTION Super absorbent polymers (SAPs) are compounds that absorb water and swell into many times their original size and weight.
They are . The hydraulic performance and durability of geosynthetic clay liner containing various amounts of sodium polyacrylate polymer are experimentally studied. Sodium polyacrylate, generally known as a super-absorbent polymer, is a polymeric material with a potential .
Figure Comparison of Water and Electrolyte Absorbing Capacity of Super Absorbent Polymers .. 33 Figure Water Absorption Kinetics of Super Absorbent Polymers ..
34 Figure Superabsorbent Polymers Introduction Superabsorbent polymers (SAPs) are materials that have the ability to absorb and retain large volumes of water and aqueous solutions.
Superabsorbents are a key component of hygiene products like baby diapers or adult incontinence products, ensuring that urine is locked up and kept safely away from the skin, keeping the skin and clothes dry and clean.
Super Absorbent Polymers Market Segmentation By Product Type (Sodium Polyacrylate, Poly Acrylamide Co-polymer, Others); By Application (Disposable Diapers, Adult Incontinence products, Feminine Hygiene Products, Agriculture Products, Others) - Global Industry Analysis, Size, Share, Growth, Trends and Forecast