Preparation And Characteristion Of The Superabsorbent Polymer From Konjac Glucomannan

Superabsorbent polymers (SAP) are new type of functional polymer materials whichcan absorb and hold a large amount of water even under pressure. These materials havebeen widely used in many fields account of their excellent properties. Now SAP we usedis almost polyacrylics resin. It is weakly biodegradable, which results in the pollution ofenvironment. More and more attention has been paid to the preparation of SAP bygrafting the ethylenic unsaturated monomers onto polysaccharides. Preparation,characteristics and application of Konjac super absorbent are studied in the dissertation.1. Konjac superabsorbent (KSAP) was synthesized by aqueous solution poly-merization on conditions of potassium sulfate as initiator, N,N'-methylene-bis-acrylamide as crosslinker. The influence of the ratio of monomer and Konjac Powder, theamount of initiator and crosslinker, the neutralization degree and the temperature on theabsorbency of the KSAP was investigated. The results were as following: the ratio ofmonomer and Konjac Powder was 10:1, the amount of initiator and crosslinker were 0.15g and 0.02 g respectively. The distilled water absorbency of the KSAP is 620 g/g. It alsohad good water retention.2. The structure of KSAP was identified by FT-IR, SEM and DSC. FT-IR indicatedthat hydrophilic group was rich in KSAP, which was the product of polysaccharides ofKonjac and sodium acrylate. The SEM image showed that KSAP was continuous networkstructure. The DSC and TG indicated that the stability of KSAP was better than KonjacPowder's. The hydrogel contains free water and link water with molecular chain whichmakes it has good keeping-water property. The absorption mechanism of SAP wasconcluded and the absorption process of KSAP was discussed.3. Studies on the biogradation of KSAP: The biogradation property of KSAP wasevaluated by mould erosion and soil burying. The results indicated that microorganismcould degrade KSAP. It was friendly to environment.4. The moisture absorption and desorption of KSAP and common desiccant (silicagel and mentor-rock) were investigated in different humidity. The result indicated that the absorptivity of common desiccant and KSAP was 15% and 12% for 9 d respectively atRH=(30±3) %, T=(25±3)℃. At RH=(75±3)%, T=(25±3)℃and RH=(90±3)%, T=(25±3)℃, the absorptivity of KSAP reached 70% and 120% for 9d respectively. KSAPalso had good water retention.5. The acute oral toxicity test and dermal irritation test of KSAP was tested. Theresult indicated that the maximum tolerated dose (MTD) of KSAP was over2000mg/KgBW and was no irritation to skin.