Study On The Absorbency Of CPAAM Superabsorbents

Superabsorbent polymer (SAP) is a new kind of functional polymeric materials, because of their excellent properties, they have been used in many applications such as agriculture, horticulture, feminine napkins, sanitation, medicine, construction and soil improvement.AA and AM were graft polymerized onto the chain of CPAAM and the relationship between the absorbency and the absorbing time is investigated. The effect of types and concentrations, pH values and temperatures of the salt solutions on the balance absorbencies is discussed. The results have shown that the balance absorbency of the CPAAM decreases rapidly with increasing the concentration; the non-electrolyte solutions have little effect on the absorbency while the electrolyte solutions have greater effect on the absorption rate; the cation valence of the electrolyte solutions significantly affects the absorbency of the CPAAM; in the same concentration of solution, the effect of high valence cations is greater than that of the monovalent cations for the absorbency of CPAAM. The pH values of the salt solutions have significant effect on the absorbency:the absorbency of the CPAAM remained almost constant with the increase of pH vales from 5 to about 9 in distilled water, and are nearly platform-like, and the absorbency increases rapidly when the pH values increase from 2 to 5 and decreases rapidly when the pH values indecrease from 9 to 14. The temperature of the solution also has some affect on absorbency which increases with the increase of the temperatures of the salt solutions, the maximum absorbency is reached when the temperature is 25℃or so.Under the conditions of the natural evaporation, the water retention capacity of the CPAAM in soil or sand is investigated. The effect of mass of the CPAAM, the types of fertilizer solutions and the soils on the water retention capacities of the soil is discussed. For the same type of soil, the more the CPAAM is used, the more slowly the water retention capacities of soil has been dropped. However, the soil losing water will tend to balance when the more CPAAM is used. The applying effect of CPAAM in sand soil is still more than the soil.The structure of CPAAM was characterized by Fourier transform infrared spectroscopy (FTIR). The result has shown that acrylic acid and acrylamide monomer are grafted onto chitosan molecules.