The Preparation Of Konjac Superabsorbent Polymer And Its Structural Analysis

Superabsorbent Polymer (SAP) possesses the excellent properties such as water-absorption, water-retention. SAP is widely used in many fields, e.g. hygiene products, medicine, construct, agriculture, horticulture, food, etc. More and more attention has been paid to the preparation of SAP by grafting the ethylenic unsaturated monomers onto polysaccharides in order to decrease the environment pollutions. This paper studied on the conditions of the SAP preparation by grafting the ethylenic unsaturated monomers onto the polysaccharides of konjac flour. In addition , the structure and the biodegradable property of the SAP were tested . The main results as the follows :1 The determination of the main components of konjacThe contents of water, ash, lipid, starch, konjac glucomannan, crude fiber of konjac flour were respectively determined by infrared drying method, ignition method, Soxhlet extraction method, etc. The results indicated that the contents of the components as above were 6.72%, 4.47%, 0.56%, 29.22%, 43.51%, and 8.57% respectively. More than 80% components of konjac flour were polysaccharides.2 The preparation of konjac superabsorbent polymer (KSAP) and the test of its propertiesKSAP was prepared by grafting acrylic acid partly neutralized by sodium hydroxide onto the polysaccharides of konjac flour. The reaction was initiated by potassium persulfate (K2S2O8). The reaction products were crosslinked by N, N'- methylene bis acrylamide (NBisA). The capability of absorbing pure water for KSAP was up to 750 times and tap water 279 times under the following conditions: the mass of konjac flour 3.000g, the mass of acrylic acid 30.000g, the neutralization degree of acrylic acid 80%, the mass of initiator 0.150g, the mass of crosslinker 0.050g, the reaction temperature 60 C, the time of reaction 2 hours respectively. Gel strength and water retention were acceptable.3 Structural analysis of KSAPThe structure of KSAP was analyzed by means of Fourier-transform Infrared and Scanning Electron Microscope. The results indicated KSAP was the graft productprepared by grafting sodium acrylate onto the polysaccharides of konjac flour. The graft efficiency of KSAP was 75% determined by water extraction method. 4 Studies on the biodegradation of KSAPThe biodegradable property of KSAP was evaluated by mould erosion and soil burying. The results indicated that microorganism could degrade KSAP. It was friendly to the environment.