In this paper, the isothermal crystallization kinetics of polypropylene(iPP) during self-nucleation was studied by means of differential scanning calorimetry(DSC). The iPP was melted at 438 K and then isothermally cry...In this paper, the isothermal crystallization kinetics of polypropylene(iPP) during self-nucleation was studied by means of differential scanning calorimetry(DSC). The iPP was melted at 438 K and then isothermally crystallized in the range of temperature between 421 and 425 K. The mechanism of nucleation and growth of iPP was discussed. The Avrami equation was applied to analyzing the process of isothermal crystallization of iPP from the melt. The average value of Avrami exponent is n=3.01, suggesting that the primary crystallization maybe corresponds to three-dimensional spherulitic growth.The K g value obtained from Lauritzen-Hoffman equation is 1.128×105 K2, which suggests that crystallization species should be regime Ⅱ. The decrease of crystallization active energy and chain folding work indicates that the self-nucleation can greatly promote the overall crystallization of iPP.展开更多
文摘In this paper, the isothermal crystallization kinetics of polypropylene(iPP) during self-nucleation was studied by means of differential scanning calorimetry(DSC). The iPP was melted at 438 K and then isothermally crystallized in the range of temperature between 421 and 425 K. The mechanism of nucleation and growth of iPP was discussed. The Avrami equation was applied to analyzing the process of isothermal crystallization of iPP from the melt. The average value of Avrami exponent is n=3.01, suggesting that the primary crystallization maybe corresponds to three-dimensional spherulitic growth.The K g value obtained from Lauritzen-Hoffman equation is 1.128×105 K2, which suggests that crystallization species should be regime Ⅱ. The decrease of crystallization active energy and chain folding work indicates that the self-nucleation can greatly promote the overall crystallization of iPP.
