With initiator of ammonium persulfate, acrylic acid was graft polymerized on the chain of carboxymethyl chitosan.After crosslinked with N,N′-methylene diacrylamide and gas foamed with NaHCO3, a kind of novel superabsorbent polymer with macroporous structure, CMCTS-g-PAA, was prepared.The Voigt model was used to characterize the swelling kinetics of the polymer.The significance of the parameters in the Voigt model in the process of swelling was explained.By studying the swelling kinetics and characterizing the polymer with SEM, the effects of the amount of NaHCO3, matching of adding time of NaHCO3 and gelation time on the swelling properties and surface morphology of the polymer were discussed.
In this paper,an innovative method to study the structure of the porous superabsorbent polymers was studied.By using the Image J image processing software,the SEM pictures of the polymers were transformed into a binary sketch image.The structure parameters of the pores could also be calculated with the aid of the software.According to the principle of differential box counting,combined with the MATLAB programming,the fractal dimension of the porous superabsorbent polymers could be obtained through the binary sketch image.The calculated fractal dimension could be used to express the regularity of the complicated structure of the porous superabsorbent polymers.Via the above process,the influence of the pre-swelling time for the porous superabsorbent polymers,prepared through the cryogenic induced phase separation method,on the structure of the modified polymer was discussed.
