Effects Of Polymerization Methods On The Adsorption Properties Of β-cyclodextrin-based Polymers To Organic Dyes

In this paper, the reaction of cross-linking β-CD with crosslinker ethanediamine maleamic acid and β-CD with styrene-maleic anhydride alternately copolymer(SMA) on the skeleton as the research object have been studied. And the effects of polymerization methods on the adsorption properties of β-cyclodextrin-based polymers to organic dyes were discussed.1. The crosslinked β-cyclodextrin polymer(PCD) was synthesized by cross-linking β-cyclodextrin with ethanediamine maleamic acid by methods of inverse-emulsion polymerization and reaction-decompression distillation which was proposed in this paper. The influences of reaction conditions including feeding ratio, solvent quantity, reaction time before decompression, and vacuum distillation temperature on the yield and performance of polymer adsorbing MB were studied. The results showed that in the reaction system when n(β-CD) was 2mmol, n(β-CD):n (cross-linking agent) was 1:3.5, V(DMF) was 25 mL, reacted at 70℃ for 4h, and then the DMF was gradually removed under reduced pressure distillation at 70℃ for 4h to prepare polymer(D-PCD) with the best adsorption performance and the yield of 68%.The influences of inverse emulsion polymerization conditions such as feeding ratio, alkali concentration and reaction time on the yield and performance of E-PCD adsorbing MB were studied. The best polymerization condition has been defined that n (β-CD):n(cross-linking agent) was 1:4, alkali concentration was 2.5mol·L-1 and reacted at 70℃.2. The β-CD immobilization polymer (D-PSMACD) was synthesized via the reaction of β-CD with styrene-maleic anhydride alternately copolymer(SMA) by methods of reaction-decompression distillation. The results showed that in the reaction system when n(β-CD) was 3.1mmol, n (β-CD):n (SMA) was 1:1.75, V(DMF) was 20 mL, reacted at 70℃ for 5h, and then the polymer(D-PSMACD) was produced under reduced pressure distillation at 75℃ for 3h with the best adsorption performance of MB and the yield of 48%.3. The polymers was characterized by IR, BET, SEM and TG. Cyclodextrin and carboxyl groups content of D-PCD,E-PCD were studied and compared with the solution polymerization product(PCD). The results indicated that cyclodextrin and carboxyl groups content of E-PCD and D-PCD was lower than that of PCD. The sequence of adsorption performance to MB was D-PCD>E-PCD>>PCD. Three methods of prepare polymers have Significant differences in adsorption of MB and RhB, Especially for Rhodamine B(RhB).4. The effects of adsorption conditions such as the initial concentration, temperature, time, system pH on the performance of polymers adsorbing MB and RhB were studied. The results showed that at 25℃, the saturated adsorption amount to MB of D-PCD, E-PCD were respectively 244mg·g-1 and 226mg·g-1, saturated adsorption amount of RhB were respectively 224mg·g-1 and 190mg·g-1, the saturated adsorption amount to MB of D-PSMACD was 549mg·g-1. The adsorption of dyes was confirmed in accordance with the pseudo-second order kinetic and the Langmuir isotherm equation.