The Graft Copolymerization And Layer-by-layer Self-Assembly Based On Ovalbumin

Ovalbumin, the main components of egg, already has a steady supply. Exploring of new materials based on ovalbumin is of great significance in egg processing. These new materials play an important role in materials sciences.The structure of graft copolymerization and layer-by-layer structured nanofibrous mat of ovalbumin were characterized by FT-IR, FE-SEM, XRD, DSC and XPS. The potential value of ovalbumin in absorpting and biomedical fields was discussed. The main results indicated as follows:1. The results show the grafting rate and efficiency are46.33%and231.67%respectively, under the following optimal conditions:the quality of ovalbumin was3g, the reaction temperature was60℃, the reaction time was60min, the concentration of potassium peroxydisulfate was60mmol/L, the quality of AN was12g. The group-CN was imported onto ovalbumin after being grafted, while there is no obvious change in elementary structure. The analysis results of FE-SEM and DSC、TG indicated that the copolymers were irregular shape and the thermal stability of ovalbumin improved by graft modification.2. The absorption processes of iron, copper, and zinc could be divided into fast absorption period and stable period. The kinetic studies indicated that absorption processes of iron, copper, and zinc finally reached the adsorption equilibrium within100min,120min and120min, respectively. The absorption of graft product had characteristics of the pseudo second-order model (R2>0.99).While the data correlated with Langmuir isothermal absorption(R2>0.95). The preliminary analysis showed that the group-CN of polyacrylonitrile had great attributions to the absorption activity of the grafted product.3. Since polyacrylonitrile has great capabilities in absorpting metal ions, the sedimentation of ovalbumin onto the electrospun polyacrylonitrile mats was induced by the Ag+which had been absorbed by the mats. The peaks of carbon, nitrogen, silver, oxygen and sulfur were found in the XPS spectrum to confirm the existence of Ag and ovalbumin in the samples after the layer-by-layer coating. The result was verified by the XRD analysis. Compared with the smooth surface of the polyacrylonitrile fiber, the layer-by-layer films-coated samples showed a relatively high surface roughness on each fiber, which could be attributed to the irregular deposition of layer-by-layer films.4. Oppositely charged chitosan and ovalbumin in aqueous media deposited onto the negatively charged electrospun cellulose acetate mats alternatively. The peaks of carbon, nitrogen, oxygen and sulfur were found in the XPS spectrum to confirmed existence of chitosan and ovalbumin in the samples after the layer-by-layer coating. The layer-by-layer coating films are amorphous, which could be explained by the amorphous forms of cellulose acetate, chitosan and ovalbumin. Shifts of the melting peaks of the layer-by-layer coating films had been found in DSC.