Synthesis and Swelling Behavior of Carrageenans-Graft-Poly(Sodium Acrylate)/Kaolin Superabsorbent Hydrogel Composites
In the present paper, a novel superabsorbent hydrogel composite based on carrageenan have been prepared via graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The certain variables of the graft copolymerization (i.e. the monomer, the initiator and the crosslinker concentration as well as kaolin/carrageenan weight ratio) affected on the ultimate water-swelling capacity were optimized. The composite structure was confirmed using FTIR spectroscopy. A new absorption band at 1707 cm in the 1 composite spectrum confirmed kaolin-organic polymer linkage. The effect of kaolin amount and MBA concentration showed that with increasing of these parameters, the water absorbency of the superabsorbent composite was decreased. Because of their exceptional properties, i.e. anhydrogalactose units (13). The types of carrageenans biocompatibility, biodegradability, renewability and differ only in the position and number of ester sulfate non-toxicity, polysaccharides and proteins are the groups. Following a continuous research on modification main part of the natural-based superabsorbent of carrageenans (14), in this work, we attempt to hydrogels. The higher production cost and low gel synthesize and characterize new superabsorbent strength of these superabsorbents, however, restrict composites based on carrageenan in the presence of their application widely. To improve these limitations, kaolin particles. The preparation of the biopolymer-based inorganic compounds with low cost can be used. The superabsorbent composites can also improve the introduction of inorganic fillers to a polymer matrix mechanical properties of materials and can lower the cost increases its strength and stiffness properties. of the finished product compared with the synthetic Among inorganic compounds, special attention has counterparts as well as providing biodegradable been paid to clay minerals in the field of nanocomposites characteristics.
Synthesis and Properties of Poly(Acrylic Acid)/Montmorillonite Superabsorbent Composites
A novel superabsorbent poly(acrylic acid)/montmorillonite composite with water absorbency of about 1100 times its own weight (g H2O/g) was synthesized by graft copolymerizing acrylic acid onto ultrafine montmorillonite powder. The influence of the amount of crosslinker, montmorillonite and neutralization degree on the water absorbency of the composites is discussed in this paper.
The Open Mobile Alliance: Delivering Service Enablers for Next-Generation Applications
Apractical overview of OMA specifications and how they enable mobile multimedia services & much more ! The Open Mobile Alliance (OMA) is an industry forum, which develops open specifications to help in the creation of applications and services to be deployed over converged networks. The alliance is the leading industry forum for generating market-driven specifications for interoperable mobile service enablers that facilitate global user adoptions of mobile multimedia services. Members include traditional wireless industry segments, such as mobile operators mobile operators (e.g. AT&T, China Mobile, Orange, Sprint Nextel, T-Mobile, Telefonica, Vodafone), equipment and mobile systems manufacturers (e.g. Alcatel-Lucent, Ericsson, Motorola, Nokia, Philips, Samsung, Siemens, Sony-Ericsson), and Information Technology vendors (e.g. BEA Systems, IBM, Microsoft, Oracle Corporation, Sun Microsystems and NEC). Since its formation in 2002, the OMA has made significant progress in areas such as push-to-talk over cellular, device management, presence and group management, and messaging. The Open Mobile Alliance: Provides a comprehensive overview of the service enablers published by the OMA, tying together all the different piece parts developed by the individual working groups Offers a thorough introduction to the OMA Service Environments (OSE) and the specification process for enabling technologies. Discusses enablers for services such as gaming, IMS, Parlay, mobile broadcast and web services. Contains contributions from all stakeholders in the mobile application value chain. The Open Mobile Alliance Alliance is an invaluable resource for OMA members, product managers, network architects and planners, standards managers, standards engineers and IT professionals. Advanced Students and lecturers on mobile application development and standardization courses will also find this book of interest."The success of OMA is due to its individual members' contributions, and this book is testament to their hard work. The individual members' efforts and the authors of this book are to be congratulated on their magnificent achievements." Mark Cataldo, Senior Advisor, Orange SA, OMA Technical Plenary Chairman