| With the rapid development, polymers are becoming more and more important in our daily life and are used in many fields for its excellent properties. But most synthetic polymers do not degrade in nature, which cause environment pollution. It is impending to put new polymer materials into use. It can be foreseen that natural polymers being capable of regeneration, will play a significant role in the future. Therefore, natural polymer materials have attracted much attention recently. Among natural polymer materials, cellulose, starch and chitin exist extensively. A lot of research has been focused on starch due to its advantages such as regeneration, biodegradability, easy accessibility and low cost.In this paper, a novel way using glacial acetic acid, acetic anhydride and methylsulfonic acid (MSA) as esterification catalyst is applied to synthesize high amylose starch acetate with high degree of substitution (DS). Starch acetates with high DS are obtained by monitoring reaction conditions. The influences of reaction conditions such as reaction time, reaction temperature, ratios of reactants, etc on the synthesis of high amylose starch acetate are discussed. It can be concluded that prolonged reaction time, suitable using level of MSA, and suitable ratio of acid to anhydride may raise DS; prolonged reaction time has little effect on starch degradation while elevating reaction temperature will degrade starch severely. The structures of the starch acetates have been characterized by FTIR, DSC, X-ray diffraction measurements. Infrared spectra show that the hydroxyl groups of the samples are really substituted since the stretching peak of hydroxyl around 3500cm-1 decreases dramatically with the increase of DS. The distinguished stretching peak of acetate around 1380 cm-1 and 1240 cm-1 both show that acetic group is really introduced into starchstructure. The results of X-ray diffraction show that the crystal structure of high amylose starch and the starch acetate differs greatly, which implies that the crystal structure is damaged during substitution. The results of DSC show that the melting point of the starch acetate is much lower than that of the high amylose starch. This implies that the acetate modification improve the thermoplastic processing properties of the high amylose starch efficiently.The dynamics of acetic esterification has been tested by titration of the reactants. The kinetic equation of the esterification has been established according to the second-order reaction mechanism. The influences of reaction temperature, reaction time, ratios of MSA and ratios of acetic acid have been studied. The results show that elevating reaction temperature, increasing the amount of MSA will increase the reaction rate constant. But the ratio of acetic acid has little effect on the reaction rate constant.As one of the most important biodegradable materials, PCL is used to blend with starch acetate to improve its mechanical properties in this paper. DSC result shows that starch acetate and PCL are partly miscible, and there are some interactions between the two components. The addition of starch acetate hinders the order stack of PCL molecular chain. The melt points of the PCL in the blends decrease. The isothermal crystallization kinetics of the blends are studied by DSC and polarized microscope with a hot stage. The results show that crystallization temperature and starch acetate have little effect on the nucleation and crystalline growing mode of PCL. However, the crystallization rate constants decrease with the increasing of the crystallization temperature. The non- isothermal crystallization kinetic treatments get the similar results with that of the isothermal study.The blends of starch acetate/PCL are spun into fibers in this paper. The properties of fibers are characterized by sound velocity test, mechanical test and X-ray diffraction measurement. With the increase of drawing ratios the degrees of orientation increase, especially for the blend fibers. After drawing, the degree of crystallization of...
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