6480(Print), ISSN (Online) Volume 4, Issue 7, November December (2013), IAEME ENGINEERING AND TECHNOLOGY (IJARET)

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International INTERNATIONAL Journal of Advanced Research JOURNAL in Engineering OF ADVANCED and Technology RESEARCH (IJARET), ISSN IN 0976 ENGINEERING AND TECHNOLOGY (IJARET) ISSN 0976-6480 (Print)

1 International INTERNATIONAL Journal of Advanced Research JOURNAL in Engineering OF ADVANCED and Technology RESEARCH (IJARET), ISSN IN 0976 ENGINEERING AND TECHNOLOGY (IJARET) ISSN (Print) ISSN (Online) Volume 4, Issue 7, November - December 2013, pp IAEME: Journal Impact Factor (2013): (Calculated by GISI) IJARET I A E M E SUPER ABSORBENT FIBRE- OVERVIEW AYODYA KAVITHA 1, DAKURI ARJUN 2, M.N FARHEEN 3 1 Assistant Professor, University college of Technology, Osmania University, Hyderabad ,3 University college of Technology, Osmania University, Hyderabad INTRODUCTION Super absorbent fibre is a new generation fibre which has gained its prominence for its super absorption capacity. Super absorbent polymers (SAP) have the ability to absorb and retain large volume of water and aqueous solution, this unique property makes them use in water absorbing applications i.e baby nappies. It is white in colour and possesses improved handling properties to be used in a wide range of fabrics. It provides extreme high rates of water and saline uptake. Because of its extreme water absorption capacity, it is used widely in diapers and filter products. Fig: 1. Super Absorbent Material Courtesy: specialityfabricsreview.com 85

2 MANUFACTURING PROCESS Super absorbent fibre can be manufactured in two ways: 1. By modification of existing fibres or polymers 2. By using super absorbent polymers By Modification of Existing Fibres or Polymers In this method fibres are modified by hydrophilic modification i.e. incorpating hydrophilic polymers in the existing fibre forming polymers. But most of the super absorbent fibres are produced using super absorbent polymer. By Using Super Absorbent Polymer Super absorbent polymers are the polymers which can absorb high amount water/ liquid and retain them. It can absorb up to 500 times of its own weight of water. Super absorbent polymers are cross-linked so that they are insoluble in the liquid which they absorb because the liquid absorbed should be retained strongly and exertion of pressure should not cause the liquid to move out. Fig: 2. Super Absorbent Polymer Courtesy: nptel.iitm.ac.in/courses/ /17 Super absorbent polymers were earlier made by grafting polyelectrolyte s onto starch or cellulose which had good absorption capacity. But now they are made of sodium polyacrylate or partially neutralised acrylic acid. Depending upon the precise structure of polymer network and cross link density, the swelling and elasticity properties change from polymer to polymer. ABSORPTION MECHANISM The mechanism of absorption of super absorbent polymer is molecular diffusion of water into the particles of polymer chains. Because of ionization of neutralised acrylic acid, the liquid is forced 86

3 to move inside the polymer. This ionization caused by the diffusion of water inside the hydrophilic polymer results in negative carboxylate ions and positive sodium ions. Mutual repulsion of carboxylate ions and increase in osmotic pressure in the gel is caused which results in expansion and swelling of polymer chain. Solubilisation of polymer in water is prevented by cross-links. The crosslinks also control the extent of swelling or absorption by restricting infinite swelling. Fig: 3. Water Absorption Mechanism in Super Absorbent Polymer Courtesy: nptel.iitm.ac.in/courses/ /17 PREPARATION OF SUPER ABSORBENT POLYMER Super absorbent polymers are prepared by free radical initiated polymerization of partially neutralised acrylic acid along with a co-monomer and cross-linker. Polymerization technique: Bulk polymerization, Solution polymerization and inverse suspension polymerization, any one of the technique can be used. Bulk polymerization involves the use of monomer-soluble initiators and it is the simplest technique. High degree of polymerization is achieved because of high concentrations of monomer. This technique produces polymer with high molecular weight and high porosity. After the polymer is produced the next step is to extrude the melted polymer through spinnerette with the help of hot air stream and then evaporation (drying and curing) of water produced cylindrical particles (fibres) of precise diameter. Later these fibres are precisely cut according to the required staple length. 87

4 Process flowchart for manufacturing of SAP Raw materials Polymer manufacture (Acrylic acid and methylacrylate are polymerised to form polymer) Extrusion Drying and curing of fibre Cooling Cutting to précised staple length Finishing (Thermal conditioning) PROPERTIES OF SUPER ABSORBENT FIBRE Important properties of super absorbent polymers are listed below 1. Swelling capacity 2. Elastic modulus of the swollen cross linked gel The above properties are related to the cross link density, the modulus increases and swelling capacity decreases with increasing crosslink density. The absorption is also increases in the degree of neutralization of carboxylic acid groups. Fig 4. Shows the change in swelling capacity Fig: 4. Change in swelling capacity with increase in a) Cross linker concentration b) Degree of neutralization 88

5 The general range of physical properties of super absorbent polymer in Table 1. Table.1 Physical Properties of Super absorbent polymers Staple length Colour white 6mm, 52mm and 80mm Moisture regain (typically 10) ph (saline extract) 5.5 tenacity extensibility 5% 10cN/tex Courtesy: Super absorbent fibre can be converted into numerous fabrics using the following web-forming processes: Air-laid Dry-laying carded Staple fibre manufacture Wet-laid To meet the customer requirements super absorbent fibre can also be blended with a full range of synthetic and natural fibres. Following the web-forming process, super absorbent fibre webs can be bonded as follows to allow for the formation of an extremely diverse fabric. Needle-punched Thermally bonded Stitch-bonded Latex-bonded Steam/calendar bonded Bonding combinations 89

Applications Agrotextiles - Agro bags, Water reservoir fabrics

Water proofing fabrics Industrial Textiles - Filter Products

Incontinence products, Gauze, Bandages Packaging Textiles - Meat

6 Applications Agrotextiles - Agro bags, Water reservoir fabrics Construction textiles- Heat insulating fabrics Geotextiles - Water proofing fabrics Industrial Textiles - Filter Products Medical textiles - Dental absorbent products, Diaper, Incontinence products, Gauze, Bandages Packaging Textiles - Meat Packaging Bag, Fruit packaging bags, Medical testing Kits, Diagnosing Packaging 90

Protective Textiles - Protective Cables, Flame Retardant fabrics, Ballistic Materials Sports Textiles- Breathable Fabrics, Phase Change Fabrics Courtesy: www.jcxw.cn/english/03_products/proshow.asp?

7 Protective Textiles - Protective Cables, Flame Retardant fabrics, Ballistic Materials Sports Textiles- Breathable Fabrics, Phase Change Fabrics Courtesy: REFERENCES 1. B. J. Agarwal, Eco-Friendly Dyeing of Viscose Fabric with Reactive Dyes, International Journal of Advanced Research in Engineering & Technology (IJARET), Volume 1, Issue 1, 2010, pp , ISSN Print: , ISSN Online: K.L. Jeyaraj, C. Muralidharan, T. Senthilvelan and S.G. Deshmukh, A Hybrid Business Strategy Selection Process for a Textile Company using Swot and Fuzzy ANP A Case Study, International Journal of Management (IJM), Volume 3, Issue 2, 2013, pp , ISSN Print: , ISSN Online: Kh. EL-Nagar and Mamdouh Halawa,, Effect of Mordant Types on Electrical Measurements of Cotton Fabric Dyed with Onion Scale Natural Dye, International Journal of Electrical Engineering & Technology (IJEET), Volume 3, Issue 2, 2012, pp , ISSN Print : , ISSN Online: nptel.iitm.ac.in/courses/ /

Atmospheric plasma treatment for surface modification of fibre assemblies

Atmospheric plasma treatment for surface modification of fibre assemblies Aasim Ahmed Research Assistant Textile Research & Innovation Centre Textile Institute of Pakistan 1 Textile Institute of Pakistan