Study On Preparation, Characterization And Properties Of Polysaccharide Polymeric Modified Materials

Renewable resource polymers come from the biomass produced by solar energy. They are inexhaustible and renewable; the essential of the research and exploitation based on natural polymers actually is the research, exploitation and conversion of ecologic resource and energy. Nowadays, the petroleum and coal resources are being exhausted gradually, and the environmental pollution from the deposit of non-biodegradation synthetic polymers is becoming more and more serious. Therefore the research and development of new materials based on renewable polymer has been evaluated as an effective method to solve the existing problems. This paper reviewed the recent proceeding, current research development and application of chitin, chitosan, and their new materials. The main contents and conclusions in this paper are as follows: Chitosan with degree of deacetylation (DD) of 85% was obtained by deacetyling from chitin, and the fiber of chitosan and chitoan/gelatin were prepared by solution filature. The structure of the fibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). scanning electron microscopy (SEM), and positron annihilation lifetime spectroscopy (PALS), and the property of the fibers were investigated by the tensile test, lysozyme degradation examination and blood compatibility experiment. There is strong interaction between chitason and gelatin in the blend fibers. Therefore there is a negative derivation of the fractional free volume for the blend films from the strait line between the fractional free volume of film chitosan and gelatin, indicating a constriction of free-volume hole size in the blend due to good miscibiliry of two polymers. Tensile strength (at,) of blend fibers sharply increases while breaking elongation (Sb) decreases with the content of gelatin increases. Especially when the content of gelatin reaches 30% (wt). the Ob of blend fiber in dry and wet states reaches maximum values. 1.99cN/d of Ob.ctry and 0.98cN/d of Ob.wet respectively, which are enhanced by 41% and 44% compared to the chitosan fiber. At the same time, the physical crosslink due to intermolecular strong interaction restrictes the degradation rate of lysozyme. The compatibility of the blend fibers greatly enhances with the introduction of gelatin.Base on the above facts, the composite fibers of chitosan/gelatin are to be used in medical field as seam.A series of chitosan/SiO2 composite films with good mechanical properties and biodegradation were prepared successfully by solution cast method. The results of measurements indicate that with the proper addition of SiO2 sol-gel, the dry and wet tensile strength of composite films is improved greatly. When mass percent of SiO2 reaches 8%. the best values are 49.05MPa and 27.57MPa, which increase 28.54% and 9.53% respectively compared with chitosan film(38.16MPa.25.17MPa respectively). The soil degradation test shows that chitosan/SiO2 composite films have reasonable biodegradability. SEM photos show that the biodegradation occurs from the surface of the films and gradually develops to the inside of them. The biodegradation of the composite films is closely related to the composition of the films. The rate of the biodegradation of the composite films decreases with the content of SiO2 increases. This can be attributed to the hydrogen bond and crosslink networks between the molecules of chitosan and SiO2 These composite films with good mechanical properties and biodegradation are to be used as agricultural films.A composite plastic based on soy protein isolated (SPI) and chitin (CH) was prepared with plasticization of glycerol by blending and compression-molding. Although the increase of CH content results in an enhancement of tensile strength and Young's modulus, the incorporation of CH decreases the breaking elongation of the materials. When the CH content is higher than 10 wt%, the water absorption of SP-C sheets are obviously lower than SP-CO without CH. The added CH cannot strongly interact with SPI molecules, and...