title: Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.
abstract: Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications.
authors.affiliation: Department of Polymers and Pigments, National Research Centre, Dokki 12622, Cairo, Egypt. Electronic address: hessawy@hotmail.com.
authors.forename: Hisham A
authors.initials: HA
authors.lastname: Essawy
authors.affiliation: Department of Chemistry, Faculty of Science, El-Azhar University, Nasr city, Cairo, Egypt.
authors.forename: Mohamed B M
authors.initials: MB
authors.lastname: Ghazy
authors.affiliation: Department of Chemistry, Faculty of Science, El-Azhar University, Nasr city, Cairo, Egypt.
authors.forename: Farag Abd
authors.initials: FA
authors.lastname: El-Hai
authors.affiliation: Department of Chemistry, Faculty of Science, El-Azhar University, Nasr city, Cairo, Egypt.
authors.forename: Magdy F
authors.initials: MF
authors.lastname: Mohamed
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry; D000327:Adsorption; D002482:Cellulose / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004553:Electric Conductivity; D005308:Fertilizers; D020100:Hydrogels / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D009584:Nitrogen / Q000032:analysis; D010710:Phosphates / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis; D058105:Polymerization; D011188:Potassium / Q000032:analysis; D017680:Potassium Compounds / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D005308:Fertilizers; D020100:Hydrogels; D009566:Nitrates; D010710:Phosphates; D017680:Potassium Compounds; D012987:Soil; D014867:Water; D010758:Phosphorus; C006903:carbopol 940; D002482:Cellulose; D048271:Chitosan; C013216:potassium phosphate; C036658:acrylic acid; D009584:Nitrogen; D011188:Potassium; C006568:ammonium nitrate
keywords: Acrylic acid; Crosslinked chitosan-cellulose; Grafting; Slow release; Soil fertilizers; Superabsorbent