Preparation And Properties Of Starch/sodium Alginate Composite Superabsorbent

The current situation of water resources utilization in the world is not optimistic,and the world is also actively developing water-saving precision agriculture,and superabsorbent polymers has an active role and great development potential in the fields of water storage,water retention and the development of precision agriculture.Therefore,in order to develop a superabsorbent polymer with excellent performance,this paper synthesized a low-cost and eco-friendly superabsorbent composite(SAPC)by free radical polymerization of the natural polymer starch(ST)and sodium alginate(SA),kaolin(KL)and acrylic acid(AA)in aqueous solution.The chemical structure and morphology of the SAPC were analyzed and characterized.Infrared(FT-IR)spectra confirmed the success of the polymerization reaction.Scanning electron microscope(SEM)images show that the surface of SAPC is rough and porous,which is conducive for liquid to enter the polymer network.X-ray diffraction(XRD)patterns show that KL is uniformly dispersed in the polymer matrix.The thermogravimetric analysis(TGA)spectra shows that the addition of KL improves the thermal stability of SAPC.The influence of different reaction conditions on the water absorption of SAPC were systematically studied.When the mass of SA,KL,potassium persulfate(KPS)and N,N?-methylenebisacrylamide(MBA)are 15 wt.%,4 wt.%,0.9wt.%and 0.15 wt.%of AA,respectively,the reaction temperature is 70 ^oC,the reaction time is 3 h,the neutralization degree of AA is 80%,SAPC has the best water absorption performance,and the maximum water absorption rate can reach 1200 g g^-1.The performances of SAPC under different environments has been tested and results show that this new SAPC has excellent swelling capacity,high water retention,good salt tolerance in monovalent salt solution(Na Cl solution),good p H sensitivity and reswelling capability.The swelling behavior of SAPC was studied.The result show that the non-Fick diffusion model and the pseudo-second order kinetic model can be used to evaluate the swelling behavior of SAPC.