Studies On The Preparation Of Compound Starch-based Superabsorbent Polymer

Superabsorbent polymer or high water-absorbing resin is a type of high polymers which take a variety of hydrophilic groups, such as–OH,–COOH,–CONH2,–SO3- etc. And superabsorbent polymer could absorb a large amount of water in which the absorbed water was hardly removable.This paper reported that two kinds of materials were used to prepare a kind of compound high water-absorbing resin production through mixing, gelatinizing, making section, crushing and sieving by certain proportions.Firstly, the reaction conditions of oxidized starch-acrylic acid-AMPS graft copolymer were studied. Effect of the mass ratio of acrylic acid and oxidized starch, the addition quantity of AMPS and acrylamide, the amount of cross linking agent and initiator on graft copolymerization reaction and water absorption of superabsorbent polymer resin was researched. The optimum of graft copolymerization reaction condition was gotten through orthogonal experiment: the mass ratio of oxidized starch-acrylic acid-AMPS graft copolymer and cross linked carboxymethyl starch was 1.25, the mass of AMPS and AM was both 5 g, the amount of cross linking agent and initiator was both 0.2 g. The absorption for physiological brine was 135.46 g/g.Secondly, the reaction conditions of cross linked carboxymethyl starch were studied. Effect of ethanol concentration, the amount of sodium hydroxide, sodium chloroacetate and epichlorohydrin on degree of substitution, reaction efficiency, viscosity, the time digested byα-amylase and sedimentation volume. The optimum of reaction condition was gotten through orthogonal experiment: the mass of starch was 60g, ethanol concentration was 87%, the addition quantity of ethanol solution of sodium chloroacetate and epichlorohydrin was 0.5 mol,0.1 mL, reaction time at 60℃was for 3 hours. The degree of substitution was 0.5122.Thirdly, the reaction conditions of compound starch-based superabsorbent polymer were studied. Effect of the mass ratio of oxidized starch-acrylic acid-AMPS graft copolymer and cross linked carboxymethyl starch, water addition quantity for gelatinization, the time of gelatinization and drying temperature on the absorbency for physiological brine and the time digested byα-amylase were discussed. The optimum of reaction condition was gotten through orthogonal experiment: the mass ratio of oxidized starch-acrylic acid-AMPS graft copolymer to cross linked carboxymethyl starch was 8, water addition quantity for gelatinization was 500 g/g, the time of gelatinization was 25 min, and drying temperature was 150℃. Its absorbency for physiological brine was 113.26 g/g and it could entirely be hydrolyzed by enzyme in 20 min.Finally, the structure of compound starch-based superabsorbent polymer was researched with modern instruments: infrared spectrum, scanning electron microscope and X-ray diffraction.