| The preparation of a new type of modified polyacrylamide-based material has been demonstrated in this paper. One method is to prepare a series of amphoteric polymers by conventional polymerization, then they were used to establish an open tubular immobilized pH gradient and to carry on capillary isoelectric focusing for seperation and analysis of standard peptide mixtures, standard protein mixtures,the actual human serum sample.Another method is to prepare the modified polyacrylamide-based cryogels by polymerization at -20 ℃.Then the modified polyacrylamide-based cryogels were used in the catalyzed synthesis of methyl oleate. It was specifically composed of the following four parts:1. The preparation and characterization of immobilized pH gradient ColumnHere we research a new method to achieve an immobilized pH gradient in the form of open tubular style. Acrylamide, N, N-methylene double acrylamide have been mixed together, added with the acrylic acid and allyl amine to modified the polymers, ammonium persulfate and sodium bisulfite have been used as initiators to make mixed monomer solutions. These solutions were respectively introduced in methacrylsiloxane-modifidied capillaries or in container copolymerization at 45 degrees celsius. By altering the addition amounts of acrylic acid and allyl amine differently charged amphoteric polymers and columns were obtained.Then the prepared polymers and columns was characterized with digital cameras, scanning electron microscopy (SEM), Infrared Spectroscopy(IR), acid-base titration, thermogravimetric analysis(TGA).2. Isoelectric focusing with an open tubular immobilized pH gradientHere we achieve an immobilized pH gradient in the form of open tubular style research by a new method to connect modified capillary columns with polymers of different pis and get pH range from 2.97 to 10.54.The polymers not only modified the capillaries but also acted as focusing media. A rapid, CAs-free CIEF is available in this open tubular immobilized pH gradient. At the same time, nonspecific adsorption and protein precipitation are limited because of the hydrophilicity and open tubular feature of the polymers. Comparing with their packed partners, we find the open tubular stationary phases retain analytes by just a thin polymer film and exhibit a significant performance advantage.It was successfully used to separate satandard polypeptide mixtures, standard protein mixtures, the actual human serum etc amphiphilic molecules biological samples.3. Preparation and characterization of modified polyacrylamide-based cryogelsAcrylamide, N, N’-methylene double acrylamide, acrylic acid and allyl amine have been mixed together, ammonium persulfate and sodium bisulfite have been used as initiators by polymerization.and Then put the solution into the refrigerator reaction at at -20 ℃ to get ice gel material.Here, we get three types of frozen gel (acid, amphoteric, basic aryogel) by adjusting the ratio of allyl amine and acrylic acid. Then the prepared cryogels were characterized with digital cameras, scanning electron microscopy (SEM), Infrared Spectroscopy (IR), acid-base titration, thermogravimetric analysis (TGA) Surface Area and Porosity Analyzer (ASAP), Mercury Intrusion Porosimetry (MIP).The ratio of monomer have also been discussed. The experimental results show that neutral, with the mass ratio of N, N-methylene double acrylamide and acrylamide 1:2 are the best synthetic conditions for polymer. Then the prepared immobilized lipase was characterized with scanning electron microscopy (SEM). Finally, the best preparation conditions were respectly reaction temperature -20 ℃, deionized water 20mL, Acrylamide 0.450g, N, N-methylene double acrylamide 0.225g, ammonium persulfate 0.060g and sodium bisulfite 0.030g for acid ice gelc:acrylic acid 700uL; for amphoteric frozen gel: acrylic acid 700uL and allyl amine 700uL;and for basic aryogel:allyl amine 700uL.4. Synthesis of methyl oleate catalyzed by modified polyacrylamide-based cryogelsThe prepared cryogels were used for application of catalyzed transesterification of triolein. Then triolein was catalyzed by the different ice gel catalysts for synthesis of methyl oleate and different chromatograms can be obtained. The experimental results show that the different cryogels have a certain catalytic effect on glycerol trioleate. Therein cryogel A、B、C、exhibited the highest yield of methyl oleate is about 14.82%,21.73%,74.28. Certainly there is still room for improvement.cryogel catalysts could be promising due to the inherent features of these materials:macroporous structure, adjustable hydrophilicity and hydrophobility, and flexible choice and combination of catalytic groups.. Then the influence of different experimental conditions (the catalytic reaction time, reaction temperature etc) on the methyl oleate catalytic yield has also been discussed. Finally, We studied the best reaction conditions:the best catalytic time 12h, methanol to oil ratio 9:1, the amount of catalyst mass 5.0%(wt), the best catalytic temperature 55 ℃.The lots of feathers as stated above. We can also try to apply them to other oil from different sources.So presumably the cryogel will have a broad application prospect of biodiesel production. |
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