The multiple melting-peak behavior of polypro-pylene(PP)in nano-CaCO_(3)/PP composites and modified nano-CaCO_(3)/PP composites were investigated under the con-dition of isothermal crystallization and nonisothermal cr...The multiple melting-peak behavior of polypro-pylene(PP)in nano-CaCO_(3)/PP composites and modified nano-CaCO_(3)/PP composites were investigated under the con-dition of isothermal crystallization and nonisothermal crystal-lization.The result indicated that the addition of nano-CaCO_(3) markedly increased the crystallization temperatures of PP and induced the formation of the b-crystal of PP.The crystalliza-tion temperatures of nano-CaCO_(3)/PP composites modified by reactive monomers were further increased,but the melting-peak intensity of the b-crystal of PP was not greatly influenced.While in the presence of dicumyl peroxide,nano-CaCO_(3)/PP composites modified by reactive monomers led to the significant increase in the melting-peak intensity of the b-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 a-crystal or b-crystal during the crystallization of PP.With the increase of crystallization tem-peratures,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-CaCO_(3)/PP composites.While in modified nano-CaCO_(3)/PP composites crystallized at higher temperature,the inten-sity 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.展开更多
文摘The multiple melting-peak behavior of polypro-pylene(PP)in nano-CaCO_(3)/PP composites and modified nano-CaCO_(3)/PP composites were investigated under the con-dition of isothermal crystallization and nonisothermal crystal-lization.The result indicated that the addition of nano-CaCO_(3) markedly increased the crystallization temperatures of PP and induced the formation of the b-crystal of PP.The crystalliza-tion temperatures of nano-CaCO_(3)/PP composites modified by reactive monomers were further increased,but the melting-peak intensity of the b-crystal of PP was not greatly influenced.While in the presence of dicumyl peroxide,nano-CaCO_(3)/PP composites modified by reactive monomers led to the significant increase in the melting-peak intensity of the b-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 a-crystal or b-crystal during the crystallization of PP.With the increase of crystallization tem-peratures,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-CaCO_(3)/PP composites.While in modified nano-CaCO_(3)/PP composites crystallized at higher temperature,the inten-sity 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.
