Preparation And Chromatographic Characters Investigation Of Monoliths Polymerized By Living/control Radical Polymerizations

How to obtain uniform structure and good permeability polymeric monolith is the keyfactor for the wide application of monolith. Classica radical polymerization has the followingcharacters: slow initiation, quick growth and easy chain transfer, which lead the nonuniformstructure. In order to solve this problem, living-control radical polymerizations have beenused in this paper to prepare monoliths. Moreover, the chromatographic characters have beenstudied.A strong cation-exchange poly(vinyl ester resin-co-ethyleneglycol dimethacrylate)(Poly(VER-co-EDMA)) monolithic column has been prepared firstly by atom transfer radicalpolymerization (ATRP) without the expensive complexing ligand, in which vinyl carboxylatewas used as the monomer, ethyleneglycol dimethacrylate as the cross linking agent, carbontetrachloride as the initiator and ferrous chloride as the catalyst. Conditions of thepolymerization have been studied and optimized. Morphology of monolithic materials wasstudied by scanning electronic microscopy. Chemical groups of the monolith were assayed byinfrared spectra method and the pore size distribution was determined by a mercuryporosimeter. Moreover, the monolith was modified to bear strong-cation exchange groups andtested on the separation of human immune globulin G (IgG) from human plasma inconjunction with HPLC. Good resolution was obtained in a short time (10min) in theseparation. The effects of pH and buffer concentration on the elution of IgG have beeninvestigated. Moreover, frontal analytical method was used to get the IgG dynamic bandingcapacity of the monolith that was3.0mg/g. Besides, the monolith was also used to separatelysozyme from egg white and separate the mixture of papain, snailase and IgG. Compared toclassical radical polymerization, the monolith has more uniform structure, higher dynamicbinding capacity and better resolution.In order to avoid the cumbrous chemical modification, a novel hybrid organic–inorganicmonolith for high performance liquid chromatography (HPLC) was firstly developed by atomtransfer radical polymerization (ATRP) by a simple and rapid method, in which vinyl ester resin was used as the monomer, natrium bisulfurosum was used both as organic adjunct andcoadunate initiator to alter the activity of the free radical in the process of polymerization andthen to control the molecular mass. The conditions of polymerization were optimized. Thechemical group of the monolith was assayed by infrared spectra method, the morphology ofmonolithic material was studied by scanning electron microscopy (SEM) and the pore sizedistribution was determined by a mercury porosimeter. Finally, the monolith was used toseparate lysozyme (Lys) from chicken egg white with good resolution and reproducibilitythat were obtained in a short time (10min) by HPLC. In addition, the influences of bufferconcentration and pH value on elution have been investigated and the hybrid monolith wasused to separate benzene and its homologs from the mixture.Poly (VER-co-MMA)(vinyl ester resin–co-methyl methacrylate) monoliths havebeen prepared by ATRP and RAFT (Reversible Addition-Fragmentation Chain TransferPolymerization), respectively, to obtain more functional groups. The monoliths have beenused to separate immune globulin G from human plasma successfully. The monolithprepare by ATRP has been used to separate the mixture of α-amylasa, lysozyme, snailaseand papain. The results showed the prepared monoliths by living/control radicalpolymerization have uniform structure, good permeability and easy obtained. So theliving/control radical polymerization is a simple, convenient, efficient and cheapmethod for the preparation of polymeric monoliths.