Synthesis, Characterization and Saponification of Poly (AN)-Starch Composites and Properties of their Hydrogels

Abstract

Hydrogels based on saponified products of poly (acrylonitrile, AN)-starch composites were prepared, characterized and their water abosrbency properties examined. The term composite refered to the resultant products of polymerizatin of AN with starch in presence of ceric ammonium nitrate (CAN) as initiator, that is the composite consists of poly(AN)-starch graft copolymer, homopoly(AN) , oxidized starch and unreacted starch. Thus AN monomer was polymerized with gelatinized starch using the ceric ion method. Gelatinization of starch prior to polymerization was affected by heating certain weight of starch in certain volume of distilled water at different temperrature (65, 75 and 85°C). Polymerization was carried out under a variety of coditions. Saponification of poly (AN)-starch composites was performed in sodium hydroxide to yield the hydrogels. The water absorbency properties of these hydrogels were found to rely on variables affecting the magnitudes of both polymerization and saponification. Among these variables mention was made of the starch/liquor ratio, cocentration of ceric ammonium nitrate (CAN), monomer/starch molar ratio, duration of grafting and gelatinization temperature as well as saponification time. Hydrogels display their maximum water absorbency when granular starch was firstly gelatinized at 85°C for 30 min and secondly subjected to polymerization with AN using AN/starch molar ratio of 4.8 and CAN concentration of 10 mmol/L liquor ratio of 12.5 and thirdly sample of the so obtained poly (AN)-starch composite was saponified in sodium hydroxide (0.7 N) at 95°C for 180 min. The saponified product was then precipitated in excess methanol, dried and finally converted into powder. The product (hydrogel) in the powder form exhibited maximum water absorbency of 920 g water per gram hydrogel and 38 mL synthetic urine per gram hydrogel.

Removal of reactive dye brilliant red HE-3B from aqueous solutions by hydrolyzed polyacrylonitrile fibres: equilibrium and kinetics modelling

“…Conversely, the -OH groups and -NH groups may result during hydrolysis of some nitrile groups to a mixture of hydrophilic carboxamide (-CONH 2 ) (1668.42 cm -1 , γ C=O in amide I); and carboxylic groups (-COOH) (1408.03 cm -1 , γ C-O and δ O-H in COOH groups); the intensity of the peak at 2245.14 cm -1 for the C≡N groups decreased significantly, indicating that the nitrile groups are involved in hydrolysis reaction. The new peak at 1566.19 cm -1 is attributed to imine (-C=N-) conjugate sequences in the hydrolyzed fiber [21], in agreement with formation of partly hydrogenated naphthyridine type structures, initiated by the nucleophilic attack of -OH -on the carbon atom of the nitrile group [22]. The presence of these functional groups on the HPAN surface, proved by FTIR analysis, demonstrates that the alkaline hydrolysis of PAN is a complex process, initiated through cyclization of nitrile groups, followed by hydrolysis to amide functional groups, and finally, carboxylic groups of the -(C=N) n -segments are formed [23,24].…”

Development of Cotton Fabric with Antibacterial Properties: Part I: Preparation of Poly(acrylamide‐co‐itaconic acid) grafted Cotton Fabric and its Water Uptake Analysis

“…The higher concentration of unremoved Ce(IV) inhibits the hydrogel formation within the fabric through complexation with invading monomer molecules as well as inducing co-polymerization in the solution phase. Moreover, beside initiation Ce(IV) is also reported to participate in the termination of graft chains (19). So, it is logical to establish the fact that when Ce(IV) concentration is sufficiently higher, the free radicals speed up the termination step, thus causing a decrease in the graft yield.…”

Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid

“…Ample literature reports and both older and recent patents (Chambers, 2010;Masuda, Nishida, & Nakamura, 1978) can be found on superabsorbent production based on starches, e.g. from wheat, corn or potato (Athawale & Lele, 2000;Athawale & Lele, 2001;Hashem, Afifi, El-Alfy, & Hebeish, 2005;Masuda et al, 1978;Qunyi & Ganwei, 2005;Weaver et al, 1977;Wu, Wei, Lin, & Lin, 2003). The use of cassava starch for this application is relatively novel since only few reports have appeared so far (Lanthong, Nuisin, & Kiatkamjornwong, 2006;Parvathy & Jyothi, 2012;Sangsirimongkolying, Damronglerd, & Kiatkamjornwong, 1999).…”