Absorbency And Adsorption Of Poly(acrylate-co-acrylamide) By Solution Polymerization

The absorbency and adsorption of Superabsorbents based on poly(acrylate-co- acrylamide)(PAAAM) are investigated. The result shows that the superabsorbent PAAAM can absorb a large amount of water and has an excellent anti-salt performance. Good strength of hydrogel after absorbing in solutions and high adsorption capacities of transitional metal ions are also obtained. The main results were as follows.Superabsorbents based on poly(acrylate-co-acrylamide)(PAAAM) are prepared with N,N'-methylene-bis-acrylamide(NMBA) as crosslinker, potassium peroxydisulfate(KPS) as initiator, by means of water solution polymerization. The best polymerization conditions are obtained by orthogonal design method and step-by-step temperature-rising according to the absorbency and the strength of PAAAM after absorbing water. The maximum absorbency of PAAAM in wNaCl=0.9% aqueous solution and in distilled water is 133g?g-1 and 2710g?g-1, respectively, and the strength of PAAAM after absorbing water is also fine. The best synthesizing conditions are shown as follows: the concentration of the total monomers([M]) is 25%, the mass weight ratio(R) of AA to AM is 6:1, the neutralized degree(N) of AA is 60%, the mass weight of crosslinker([C]) and initiator([I]) compared to the total mass of monomers are 0.01% and 0.1%, respectively, and the method of raising temperature is 60℃(2h), 70℃(2h), 80℃(3h). Some important factors on the absorbency of PAAAM are discussed by single factor experimental method and regression-analysis.The relationship between the absorbency of PAAAM(Q) and the absorbing time(t) is investigated; the effect of particle size of PAAAM, species of the solutions, temperatures and solution pH on the absorbency and absorbing rate of PAAAM is discussed. The water-maintenance of PAAAM at high temperatures is also investigated.Through the research of the adsorption of Cu2+ and Fe3+ onto PAAAM, the adsorption kinetics of Cu2+ and Fe3+ onto PAAAM can be described as tThe largest adsorption capacity of Cu2+ and Fe3+ are 247mg·g-1 and 173mg·g-1, respectively. The relationship between the concentrations of metal ions and the adsorption capacities is investigated; the effect of solution pH and the mass ratio of AA to AM on the adsorption of Cu2+ and Fe3+ onto PAAAM are also discussed.Polyethylene glycol diacrylate(PEGDA) is synthesized and characterized by...