%A LIN Zhidan, ZENG Chunlian, MAI Kancheng %T Investigation on multiple-melting behavior of nano-CaCO3/polypropylene composites %0 Journal Article %D 2007 %J Front. Chem. Sci. Eng. %J Frontiers of Chemical Science and Engineering %@ 2095-0179 %R 10.1007/s11705-007-0017-5 %P 81-86 %V 1 %N 1 %U {https://journal.hep.com.cn/fcse/EN/10.1007/s11705-007-0017-5 %8 2007-03-05 %X The multiple melting-peak behavior of polypropylene (PP) in nano-CaCO3/PP composites and modified nano-CaCO3/PP composites were investigated under the condition of isothermal crystallization and nonisothermal crystallization. The result indicated that the addition of nano-CaCO3 markedly increased the crystallization temperatures of PP and induced the formation of the β-crystal of PP. The crystallization temperatures of nano-CaCO3/PP composites modified by reactive monomers were further increased, but the melting-peak intensity of the β-crystal of PP was not greatly influenced. While in the presence of dicumyl peroxide, nano-CaCO3/PP composites modified by reactive monomers led to the significant increase in the melting-peak intensity of the β-crystal of PP. The double melting-peak of PP was observed, which was attributed to the formation of two kinds of different crystallization forms of α-crystal or β-crystal during the crystallization of PP. With the increase of crystallization temperatures, the double melting-peak moved toward the high-temperature side. The intensity of high-temperature melting peak was higher than that of low-temperature melting peak in nano-CaCO3/PP composites. While in modified nano-CaCO3/PP composites crystallized at higher temperature, the intensity of high-temperature melting peak was lower than that of low-temperature melting peak. The isothermal crystallization time had little effect on the melting temperatures.