Blending Modification Of Polyethylene/Gelatin And Carboxylated Nitrile Rubber/Gelatin By Using Reactive Compatibilization

The blends of synthetic polymers and gelatin might have many combined excellent properties from each composition, but poor mechanical properties of these blended materials have been induced by their incompatibility. It has been shown that the methods used for improving the compatibility between polymer and gelatin, such as using silane-coupling agents for improving hydrophobic property of gelatin, polymerization of gelatin after unsaturation treatment with vinyl monomers had some disadvantages. As a new method of compatibilization, the reactive compatibilization has now been widely used for polymer modification. However, almost no literature has been reported about blending modification of polymer and gelatin by using reactive compatibilization. There is no doubt that it is an effective way to improve compatibility between polymers and gelatin, because many reactive groups are in molecule of gelatin. A new idea of using reactive compatibilization method for improving compatibility between polymers and gelatin to prepare biofunctionalized material by blending modification has been put forward firstly. In order to biofunctionlize polymer, polyethylene and carboxylated nitrile rubber (XNBR) were chosen as research objectives in this dissertation. The blends of PE-g-MAH and gelatin were prepared by melting process and the compatibility of PE-g-MAH and gelatin in blends were characterized. The results of FTIR showed that the characteristic absorption band peaks of amine and amide groups of gelatin were shifted in PE-g-MAH/Gelatin blends, the equilibrium values of torque were higher with the increase of blending temperature, which proved that graft copolymer PE-g-MAH-g-gelatin was formed during the preparation process, and the amount of PE-g-MAH-g-gelatin was increased with increasing the amount of PE-g-MAH. SEM micrographs exhibited that there was PE-g-MAH-g-gelatin formed in surface of gelatin phase. The results of DMA (dynamic mechanical analysis) showed that the differential values of glass transition temperature between PE-g-MAH and gelatin decreased, which indicated that the compatibility of PE-g-MAH and gelatin had been improved, and blends of PE-g-MAH and gelatin had an effect of compatibilization in situ. It was found that the blends of PE-g-MAH and gelatin obtained by melting method consisted of three components, PE-g-MAH, gelatin and PE-g-MAH-g-gelatin, the content of PE-g-MAH-g-gelatin acted as compatibilizer was about 8-16%. It was also demonstrated that mechanical properties of the blends improved with the increasing amount of PE-g-MAH, and when its amount was 80%, the blend had better mechanical properties. The reactive compatibilization of HDPE/gelatin blends was investigated with PE-g-MAH as compatibilizer. The condition of the blending process was discussed, it was shown that the fitting processing condition for blends was considered to be temperature 170 ℃, mixing time 10 minutes. The influence of the amount of PE-g-MAH on mechanical property of the blends was studied, the results showed that the addition of PE-g-MAH led tensile strength, elongation at break and impact strength of HDPE/PE-g-MAH/gelatin blends to increasing and when the amount of PE-g-MAH was 6-8PHR, the properties of HDPE/PE-g-MAH/gelatin blends increased significantly. The compatibility of HDPE/PE-g-MAH/gelatin blends was evaluated through experiments of extracting treatment and FTIR, DSC, DMA analyses. It was shown that the absorption peaks of amine and amide groups of gelatin were shifted in HDPE/PE-g-MAH/Gelatin blends because of the reaction of PE-g-MAH with gelatin. The addition of PE-g-MAH made the increase of HDPE glass transition temperature. The compatibilizing effect of PE-g-MAH was due to the crystal compatibility produced by forming the co-crystals of HDPE, PE-g-MAH and PE-g-MAH-g-gelatin.The blends of EAA and gelatin were prepared by melting process and the compatibility of the blends was also studied. The FTIR results showed that absorption peaks of amine and amide groups of gelatin were shifted in EAA/G...