Research Article Open Access

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

A. Hashem1, M. A. Afifi1, E. A. El-Alfy1 and A. Hebeish1
  • 1 National Research Centre, Dokki, Cairo, Egypt


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.

American Journal of Applied Sciences
Volume 2 No. 3, 2005, 614-621


Submitted On: 16 February 2006 Published On: 31 March 2005

How to Cite: Hashem, A., Afifi, M. A., El-Alfy, E. A. & Hebeish, A. (2005). Synthesis, Characterization and Saponification of Poly (AN)-Starch Composites and Properties of their Hydrogels. American Journal of Applied Sciences, 2(3), 614-621.

  • 40 Citations



  • Saponificaiton
  • Poly (AN)-starch Composites
  • Hydrogels
  • Water Absorbancy