Preparation of Poly[N-Isopropylacrylamide-Co-(Maleic acid)] hydrogel mambrane by electrospinning

Abstract

A copolymer of N-isopropylacrylamide (NIP A) and maleic acid (MA) acting as sites for the crosslinking was synthesized via free radical polymerization. Copolymer films of the synthesized copolymer by casting technique were fabricated, and then crosslinked with diethylene glycol DEG acting as crosslinker by a heat-induced esterification crosslinking reaction at 145°C. The solubility in water of the films was tested. The crosslinked copolymer film synthesit.ed from molar feed ratio of 35%mollmol (MA comonomerlNIPA monomer) in copolymerization process and W%wtlv (synthesized copolymer in ethanol) with 5%wtlwt (crosslinking agent DEG/copolymer), followed by a heat-induced crosslinking reaction was water-insoluble material. The yield of the synthesized copolymer was 55%. The copolymer was characterized by infrared and nuclear magnetic resonance spectroscopy and acid-base titration. Consequently, a new poly[N-isopropylaclylamide-co-(maleic acid)], poly(NIPA-co-MA) hydrogel membrane was fabricated by electrospinning the polymer solution. The effects of electrospinning parameters (e.g. applied voltage and distance between the needle and the collection screen) on the morphology and diameter of poly(NIPA-co-MA) hydrogel fibrous membranes were investigated by scanning electron microscopy. The range of the applied voltage studied was from 15 to 30 kV and the distance between the needle and the collection screen studied was from 10 to 25 cm. The optimal condition for fabrication of hydrogel membrane was the applied voltage ~t 25 kV and distance between the needle and the collection screen at 25 cm using a diameter of needle at 0.80 mm and the flow rate of I mL hour-I. The average diameter of electrospun fibers was I 17±33 nm. The hydrogel membrane which has esterification crosslinked was characterized by Infrared spectroscopy. The hydrogel membrane showed temperature sensitive property. Its minimum and maximum water absorption ratio was 4±0 g g-I at 50°C and 17±4 g g-I at 34 °C, respectively_ The electrospun membrane dissolved in water at the temperature below the lower critical solution temperature (LCST, 34°C), while the cast film did not