Effect of functional crosslinking agents on preparation and swelling properties of dextran hydrogels

摘要

Crosslinking reactions of Dextran(Dx)(M_n of 2.0 X 10~6 g mol~(-1))with some selective Cl-,and P-containing functional monomers such as epichlorohydrin(ECH)and phosphorus oxychloride(POC1_3)were carried out in the basic aqueous solutions(2.8 N NaOH)at 40 deg C.The optimum conditions of the effective swelling and crosslinking for the each system studied were found in nickel(NiCl_2(centre dot)6H_2O)solution.The percent swelling,equilibrium swelling,initial rate of swelling,swelling rate of constant,equilibrium water content,and diffusion type and constant values were evaluated for Dx/crosslinker(CL)systems at 1 mg/100 ml nickel(NiCl_2(centre dot)6H_2O)solution.A substantial difference of these parameters observed for the various Dx/CL systems was explained by the effect of nature of crosslinking agents on the mechanism of crosslinking and swelling processes.It was shown that S_eq values increase depending on the nature of CLs in the following order:ECH< POCl_3.General scheme and proposed mechanism of crosslinking reactions in the Dx/CL systems were also described.