| Summary: | 碩士 === 東海大學 === 化學工程與材料工程學系 === 105 === In this study, the isothermal and non-isothermal crystallization kinetics of Polylactic acid (PLA) and Polypropylene (PP) blend were investigated.
Our results shows that small amount of PLA lubricates PP, and accelerates PP crystallization. On the other hand, distributed PP crystal can also fix small amount of PLA molecules while crystallization, and hence works as nucleis in PLA crystallization.
Avrami equation and Hoffman-Lauritzen equation were employed to analyze the isothermal kinetics. The Activation energies of non-isothermal crystallization were calculated by Kissinger, Flynn–Wall-Ozawa (FWO), Kissinger–Akahira-Sunose (KAS) method, respectively.
Reaults showed the value of the Avrami exponents shifted from 2.5 to 3 as PLA increased, which was associated with three-dimensional spherulites crystal growth. The crystallization rate constant was composition dependent, and its value increased drastically with lower temperature. The Hoffman-Lauritzen nucleation parameters (Kg) was 3.06(deg2) for neat PP, and 1.64(deg2) for neat PLA, and blends’ value felt in between. Moreover, neat PP and neat PLA showed regime III crystallization, and the blends were all in regime II.
Non-isothermal crystallization show that, the Kissinger、FWO、KAS method determined similar activation energies, which decreased with incorporation of PLA into the blend.
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