Design, Preparation And Comprehensive Properties Of The Degradable Superabsorbent Resin

With the development of society, the environment protection has been paid more attention. In order to solve the problem of difficulty to degradable, second pollution and weak anti-salt property brought by the common superabsorbent resin, synthesizing the degradable superabsorbent resin was proposed to solve those problems in this project. Biodegradable superabsorbent polymer spheres were synthesized by inverse suspension polymerization under N2 atmosphere, using starch/sodium carboxymethylcellulose, acrylic acid(AA) and acrylamide(AM) as raw materials, N,N’-methylenebisacrylamide as cross-linking agent, cyclohexane as continuous phase, potassium persulfate as initiator. The chemical structure of synthetic copolymer was confirmed by FTIR, which ws inferred that the product was the starch/sodium carboxymethylcellulose grafted poly(AA/AM) superabsorbent resin. The competitive rate of AA(r1=0.351) and AM(r2=0.126) in the polymerization were calculated, and both values were less than 1, which indicated that the tendency of copolymerization between AA and AM existed in this system. The effects of various parameters on the water absorption of resin were investigated through orthogonal experiment method. The optimum synthetic condition for the starch system was as follows: the ratios of corn starch, initiator, crosslinking agent and dispersing agent to the monomer mass were 10%, 0.2%, 0.3% and 2%, respectively. The resulting absorption capacity for the distilled water and saline water was 379.2g/g and 88.1g/g, respectively. The optimum synthetic condition for the cellulose system was as follows: sodium carboxymethylcellulose, initiator, crosslinking agent and neutralization degree were 3%, 2%, 0.1% and 0.7 respectively.The resulting absorption capacity for the distilled water and saline was 360.2g/g and 101.1g/g, respectively.The morphology and thermal stability of the grafted resin was investigated by means of electron Microscope(SEM, TEM, OM) and thermograrimetric analysis(TGA). The results showed that the particle size of the superabsorbent polymer was about ten um and they had excellent thermal stability. The effect of various temperature on the ability of holding water for copolymer was also investigated. The results showed that the product has excellent ability of holding water. After it is used in soil, the utilization of nitrogen, phosphor, potassium was enhanced, thus, the validity of fertility was increased. From the results of absorption ability of Ca2+, Mg2+ and Ba2+ of copolymers, with the added amount of copolymers increased, the increased and tended to be stable, the optimum dosage was 0.4g and 0.5g, it possessed good effect in reducing scale depositions of Ca2+, Ba2+ and Mg2+, this could be used as the scale inhibition of superabsorbent polymer as reference. The degradation process of biodegradable superabsorbent was investigated under the condition of UV irradiation, the degradation ratio of them were 91.3% and 86.2% respectively after 100 h of irradiation, which was higher than the natural condition. The obtained superabsorbent resin was proved to be a kind of environment friendly material.