Synthesis And Adsorption Studies Of Chelating Resins With Mesogenic Groups

Chelating resins is widely used in the fields of metallary, inorganic, waste water and marine chemistry, etc. Poly(ethyleneimine)(PEI) has a good general complexing property for transition metal ions but short for its no shape and easy to flow. Branched with rigid side units, PEI is hardness and shape, hard to flow.4-hydroxy-4' -methoxybiphenyl and 4-hydroxybiphenyl were used in this paper as mesogenic side groups and reacted with PEI. Five kind of resins were synthesized and discussed the affects of reactions. IR and ~1H NMR were used to characterize the different structure, the branching degree of the mesogenic side groups on N-H units of PEI were also calculated from ~1H NMR. DSC analyses show that PN6 I -88, PN4 I -89, PN6 Ⅱ -74 show bitropic phase behavior and great thermostability. PN4 I -77 and PN2 I -91 show some mesophase. The spacer influences the mesophase behaviour. The longer of the spacer, the lower of the isotropisation transition temperature(Ti) is. The content of mesogenic units also affect the behaviour of liquid crystals. The texture was observed from polarizing microscopy indicate that the liquid crystal polymer has the schlieren texture. All polymer illustrate peaks at the 2 θ of about 20° in the X-ray diffraction which imply the exiting of crystal property. Existing hydrogen bondings, PN4 Ⅱ -76 conforms a special structure which shows peaks at the 2 θ of about 20° in the X-ray diffraction and no melting peak in the DSC before 200 °C.The adsorption properties for Hg( Ⅱ), Cd( Ⅱ), Co( Ⅱ), Cu( Ⅱ), Zn( Ⅱ) and Pb( Ⅱ) their absorptive selectivity were studied. Results show that the resins have excellent absorption and absorptive selectivity for Hg(Ⅱ), Pb(Ⅱ), Cd(Ⅱ) and Cu(Ⅱ). PN4 I -77 show a good adsorption properties for Pb(Ⅱ) because of a special structure. After quenching, the PN6 I -88 and PN4 I -89 show a higher adsorption selectivity for Hg( Ⅱ), Pb( Ⅱ), Cd( Ⅱ) and Cu( Ⅱ) which indicate the higher ordered aggregation structure improve the adsorption and the absorptive selectivity.