Temperature and Ph-sensıtıve Super absorbent Polymers based on Modıfıed Maleıc Anhydrıde

Maleic anhydride was modified with 1-decanol at two different ratios to obtain derivatives named MD-75 (75% modified) and MD-100 (100% modified). By using these derivatives and acrylamide (AAm), many hydrogels with different AAm/MD ratios were synthesized. Ammonium persulphate (APS), N,N,N′,N′-tetramethyl ethylenediamine (TMEDA) and N,N′-methylene bisacrylamide (MBAAm) were used as initiator, catalyts and crosslinker agent respectively in the synthesis reaction. The modification reactions were clarified by FTIR and 1 H-NMR methods. Swelling behaviours, swelling capacities and effect of temperature, pH of the swelling medium and hydrogel composition on these parameters were studied. The swelling capacity of the hydrogels increased up to 82700% with decreasing the AAm/MD ratio. Temperature and pH of the swelling medium and the composition of the hydrogels were found to have a strong effect on the swelling behaviour and the swelling capacity of the hydrogels. The gels showed low swelling capacity with single-step swelling behaviour at low temperatures (T≤50 °C) and high swelling capacity with two-step swelling behaviour at higher temperatures. The swelling and diffusion kinetics of the hydrogels were also determined. All of the synthesized hydrogels showed uniform diffusion type at low temperatures while two types of diffusion observed at high temperatures. Graphic abstract Hydrogels of modified maleic anhydride were prepared by chemical cross-linking. Hydrogels showed excellent swelling capacity up to 82,700%. Temperature and pH have a strong effect on the swelling capacity of the hydrogels. Hydrogels showed two-step swelling behaviour.