Study On Preparation And Properties Of Super Absorbent Polymer Based On Canna Starch Grafted By Acrylic Acid

Super absorbent polymer (SAP) are lightly crosslinking hydrophilic polymers that can absorb and retain aqueous solutions up to hundreds of times their own weight, even thousands times. In this paper, a graft copolymer was synthesized by copolymerization of acrylic acid (AA) onto canna starch, with N,N'-methylene diacrylamide as cosslinking agent and ammonium persulfate as the initiator, using traditional aqueous solution polymerization, inverse microemulsion polymerization method, microwave the polymerization, graft copolymerization of synthetic canna starch-acrylic acid super absorbent resin. The structures SAP prepared by different methods were characterized and compare the performance of SAP.The process of aqueous solution was prepared Canna starch grafted acrylic resin has been studed. Many factors such as ratios of acrylic acid to starch, initator, cross-linking agent, neutralization ratio of acrylic acid by NaOH et al were studied systemically. Which was prepared by using N,N'-meyhylene-bisacryla-mide as cross-linking agent, graft copolymerization of Canna edulis Ker starch with acrylic acid initiated by ammonium persulfate. The optimum reaction conditions were found as follows:the reaction temperature was55℃, amount of Canna starch was5.000g, onsumption of acrylic acid was40mL, the mass fraction of initiator and cross linker was3.0%and0.9%respectively in starch, neutralization degree of AA was80%. The water absorption of resin which was prepared by these optimum reaction conditions can absorb de-ionized water about684g/g.The high water absorbing resin was studied, which was prepared by using N,N'-meyhylene-bisacrylamide as cross-linking agent, through inverse microemulsio-n graft copolymerization of Canna starch with acrylic acid initiated by ammonium persulfate under condition of protection by nitrogen. When HLB=7.36, ration of Oil/H2O was1.2:1, weight fraction of emulsifier was30%, the emulsion was water-in-oil and steady. The optimum reaction conditions were found as follows: consumption of acrylic acid was16mL, the mass fraction of initiator and cross linker was3.5%and0.8%respectively in starch, neutralization degree of AA was70%. The water absorption of resin which was prepared by these optimum reaction conditions can absorb de-ionized water about1400g/g.The synthetic conditions of superabsorbent resin from Canna starch and acrylic acid under microwave irradiation were studied. Based on single factor test, using response surface methodology (RSM) to study effect ratios of acrylic acid to starch, initator, neutralization ratio of acrylic acid by NaOH on the water absorbent rate were investigated. Also the analysis to the copolymer structure had been carried on. The results showed that the optimum technological were mass ratio of monomer to starch8.2:1, initator(accounts for the proportion of starch quality)2.8%, neutralization ratio of acrylic acid80.1%, in this case, the water absorbency was769g/g.The surface sturcture and heat property were analyzed by IR, SEM etc. The analysis of IR showed that the synthesized product had carbonyl's character, which proved graft polymerizations of acrylic acid (AA) with cassava starch. X-RAY showed that the surface structure of starch became amorphous from semi crystalline. SEM analysis showed that the surface of starch was destroyed by acrylic acid (AA). The results have been proved that acrylic acid grafts into the base of starch successfully.In this paper, the evaluations of some influential factors of the SAP prepared by three different methods, such as water absorbing capacity (distilled water, tap water, normal saline), absorption rate, water holding capacity and recovery ability are researched.(1) The results show that the suction capacity of super absorbent polymer based on Canna starch grafted by acrylic acid is superior. The liquid absorption capacity of SAP prepared by three different methods in order:distilled water> tap water> normal saline, SAP polymerized by inverse microemulsion was the strongest.(2) The realization of the phenomenon shows Canna Starch Grafted Acrylic resin in the pipette within30min, the liquid absorption rate is very fast, fluid absorption rate is easing to100min after the suction fluid volume almost reached saturation. Throughout the whole process of liquid absorption, inverse microemulsion polymerization proceeds resin prepared by the suction rate was significantly better than by the conventional aqueous solution method and microwave Polymerization proceeds resin.(3) Under natural conditions, the water loss curve of the SAP's absorbent gel, which were prepared by three different methods, became linear relationship. The resin prepared by microwave polymerization had the lowest rate of water loss. The resin prepared by solution polymerization's water loss rate slightly lower than the inverse microemulsion polymerization prepared resin.(4) The experimental results show that the re-use SAP prepared by inverse microemulsion polymerization has a greater impact, the loss rate as high as70%. Microwave polymerization method for the water absorbency of the resin minimal effects, it has been very stable. Method for the solution polymerization was more stable, water absorbency and down slightly after repeated use.