聚丙烯/石墨烯纳米复合材料的等温结晶和结晶形态

Isothermal Crystallization and Crystallization Morphology of Polypropylene/Graphene Nanocomposites

研究了熔融混合制备的聚丙烯(PP)/热还原氧化石墨烯(TRG)纳米复合材料的等温结晶行为,并探讨TRG对PP等温结晶动力学、结晶的熔融行为以及结晶形态的影响。结果表明,加入TRG可显著提高体系的结晶速率,使PP的平衡熔点升高(TRG为1.5%时提高11℃),结晶度增大(TRG为1.5%时增大6.6%),结晶完善程度提高。用Avrami方程进行等温结晶动力学研究表明,参数n对结晶温度有一定依赖性且加入TRG使n值增大,TRG具有较好的异相成核作用,使PP的半结晶时间缩短60%以上。此外,复合体系中生成的球晶尺寸显著减小。

In this paper,the crystallization behavior including isothermal crystallization kinetics,the melting behavior and the crystallization morphology of polypropylene(PP)and PP/graphene were investigated by differential scanning calorimetry and polarized light optical microscopy.The results indicate that the addition of graphene decreases the crystallization time of polypropylene,obtained a higher equilibrium melting point,higher relative crystallization degree and more perfect in crystalline structure.The isothermal crystallization kinetics can be explained by Avrami equation.The value of n is related to crystallization temperature,while the half crystallization time(t1/2)of PP/graphene is observed to be much shorter than that of PP as graphene can effectively promote the nucleation of PP during its crystallization process.Besides,the spherulite sizes are also decreased remarkably.