Preparation And Properties Of Starch-based UV-curable And Rapid Degradation Superabsorbent Material

Unsaturated polyester-urea amide which was used as cross-linking agent was prepared by melt-polycondensation in this paper, and corn starch grafted acrylic acid copolymer was prepared by aqueous solution polymerization. A membranous material with high water absorption and easy degradation was prepared, when unsaturated polyester-urea amide and corn starch grafted acrylic acid copolymer were UV-curing and cross-linking under UV irradiation. In the progress of modeling, we didn’t add any photo-initiators in it, and the material has the advantages of non-toxic side effects, no residual small molecules and can be fast degradable and so on. In this paper, the effects of preparation conditions on the properties of super absoebent were studied. The polymer was characterized by IR, TG-DSC and SEM.The research results show that in the conditions of gelatinization ratio of starch and water 1:10 , w(CAN)=0.1 % (based on acrylic acid quality), reaction time of corn starch grafting acrylic acid 3 h , reaction temperature 60℃, mass ratio of acrylic acid and corn starch 6, neutralization degree of acrylic acid 90 %, mass ratio of corn starch grafting acrylic acid polymer and unsaturated polyester-urea amide 200 , UV curing time of 15 min , the superabsorbent material has fairly good water absorption capacity, water absorbency of this material in distilled water, tap water, 0.9 % KCl and 0.9 % NaCl solutions can reach to 920.58 g/g,410.73 g/g,128.70 g/g,99.13 g/g respectively in normal temperature; the superabsorbent material also has good water retention capacity, when the material immersed in distilled water, tap water, 0.9 % KCl and 0.9 % NaCl solutions to water saturation state, 24 h water retaining rate are up to 91.17 % , 83.83 % , 70.71 % and 79.93 % separately. IR confirmed that crosslinking reaction has occurred between corn starch grafted acrylic acid copolymer and unsaturated polyester-urea amide, and TG-DSC confirmed that the membranous material with high water absorption has good thermal stability.The super absorbent material has better performance in degradation than others, and it can be used in the area of disposable physiological health articles to reduce environmental pollution. In normal temperature, the weight loss rate of it can be 85.25 % , 64.73 % and 36.82 % after being immersed in distilled water, 1 mol/L NaOH solution and 0.9% NaCl solutions respectively for 7 d . The super absorbent material shows a deep hollow and three-dimensional cross-linked network structure before degradation, and it has rough and porous surface. When degradation in different solutions, cross-linked network structure has gradually disappeared, meanwhile, roughness degree increase and accompany with large cracks in the surface. It shows that, in degradation process, long chains breaking into short chains and then change into small particles gradually.