Journal of Applied Polymer Science, Vol.84, No.2, 310-317, 2002
Syntheses and properties of carboxymethyl chitosan/urea-formaldehyde snake-cage resins
A series of novel snake-cage resins were synthesized using carboxymethyl chitosan (CM-CTS) as the snake resin and urea-formaldehyde resin (LTF) as the cage resin. Such factors as the optimal synthesis conditions, content of the crosslinking agent, and sorption capacities for metal ions of the above-mentioned resins were investigated, The experimental results show that these resins have appropriate swelling properties and good mechanical stability. They do not run off in water, HCl, and NaOH aqueous solutions. To form a stable network system, NH4Cl was used as a crosslinking agent to crosslink urea and formaldehyde in synthesis. The sorption experiment showed that the sorption properties of the resins in the presence or the crosslinking agent NH4Cl are better than those without a crosslinking agent. The investigation of the FTIR spectra indicated that the chelate groups, such as -OH, -CO2- and NHCH2CO2-, in snake-resin molecules participated in the coordination with the metal ions, but the -C=O bonds in the cage resin UF did not. The snake rosin CM-CTS in the snake-cage resins was the major contributor of sorption. The sorption dynamics showed that the sorption was controlled by liquid film diffusion. The isotherms can be described by Freundlich and Langmuir equations. The saturated sorption capacities of the resins for Cu2+, Ni2+, Zn2+, and Pb2+ were 1.48, 0.78, 0.13, and 0.02 mmol g(-1), respectively.