Synthesis of pH-sensitive inulin hydrogels and characterization of their swelling properties.
In this study, pH-responsive inulin hydrogels were prepared by radical copolymerization of methacrylated inulin (MA-inulin) with acrylic acid (AAc) in aqueous solution using ammonium peroxydisulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TMEDA) as an initiation system. The AAc content in hydrogels was evaluated by FTIR spectroscopy. The covalent bridging of AAc among MA moieties of MA-inulins was observed by a significant increase in the effective network density of hydrogels and further confirmed by TGA studies. While, at a low content of AAc, the hydration of hydrogels at pH 7.4 decreased owing to the increased crosslinking density, the swelling subsequently increased with further increasing AAc as a consequence of the increased ionic osmotic pressure within hydrogels. The change in swelling of hydrogels in response to pH change between 7.4 and 2.2 was therefore enlarged when the AAc content increased.
Chiu
Hsin-Cheng
HC
Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan 402, ROC. hcchiu@dragon.nchu.edu.tw
Hsu
Yuan-Hung
YH
Lin
Pei-Jung
PJ
D000179:Acrylates / Q000737:chemistry; D000645:Ammonium Sulfate / Q000737:chemistry; D005029:Ethylenediamines / Q000737:chemistry; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007444:Inulin / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry
D000179:Acrylates; D005029:Ethylenediamines; D020100:Hydrogels; D008689:Methacrylates; D014867:Water; C031276:ammonium peroxydisulfate; D007444:Inulin; C036658:acrylic acid; D000645:Ammonium Sulfate