Synthesis And Performance Of Functional Polystyrene Beads

Polymeric beads with the function of separation, adsorption or catalysis, have been widely applied in modern industrial process such as desalination in water treatment, adsorption of metal ions in hydrometallurgy and wastewater treatment, and the catalytic reaction in chemical engineering. In this paper, an amphoteric ion exchange resin being able to exchange the anion and cation, and a supported catalyst endowed with the function of catalytic oxidation were prepared. And the performances of separation and catalysis of these two functional beads were characterized, respectively.In the first part-of this paper, an amphoteric ion exchange resin bearing semi-interpenetrating network structure, was prepared by swelling polymerization after quaternary amination reaction with the supporting material of chloromethylated beads. Effects of the crosslinking degree of chloromethylated bead, the dosage of acrylic acid and initiator as well as reaction temperature on the exchange capacity were studied by a single factor method. The results indicated that the optimal reaction conditions were:the crosslinking degree of chloromethylated bead was7wt%, the dosage of acrylic acid was2eq of quaternary ammonium groups, and the dosage of initiator was0.5%of acrylic acid and the reaction temperature was80℃. Getting the exchange capacities were: anionic exchange capacity was3.24mmol/g and the cation exchange capacity was3.33mmol/g. And the R-1resin had similar performances with the imported resin in separation and regeneration.In the second part of this paper, a supported catalyst was prepared by anchoring the bromine alkyl modified2,2,6,6-tetramethylpiperidine-l-oxyI (TEMPO) onto chloromethylated bead through ionic liquid bridge. Effects of the length of bridging chain on the thermal stability, solvent swelling and recycling of the catalyst were studied. The results showed that the supported catalyst PS-im-C6-TEMPO had good stability. It could be reused for30consecutive recycles with conversion above95%without significant loss under the condition of Montanari oxidation reaction (NaClO/NaBr, CH2C12/H2O). And PS-im-C6-TEMPO exhibited good performance for catalytic oxidation in a fixed bed reactor.