PP/PA11共混物微、介观形态的分子模拟

Molecular simulations of microstructures and phase morphologies of polypropylene/polyamide-11 blends

采用分子动力学(MD)和介观动力学(MesoDyn)模拟方法研究了不同质量含量(10/90、30/70、50/50、70/30和90/10)PP/PA11共混物的相容性和介观形态结构。通过对MD模拟得到Flory-Huggins相互作用参数和PP-PP、PA11-PA11及PP-PA11分子间C—C原子对的径向分布函数,研究表明:当PP与PA含量为90/10时两者具有一定的相容性,而其他比例的相容性则较差。为了进一步研究共混物的介观形态结构,采用MesoDyn模拟方法在介观尺度对共混体系的介观形貌进行了研究,将通过MD模拟计算的分子间相互作用参数和其他结构参数(重复单元个数、聚合度和极限特征比等)转化为MesoDyn模拟的输入参数,实现了微、介观多尺度模拟的连接。介观模拟得到的共混物形貌图进一步证实了分子动力学模拟得到的结果。

The miscibility and mesophase formation of binary polypropylene（PP）/polyamide-11（PA11）blends（with mass ratio of 10/90,30/70,50/50,70/30 and 90/10）were investigated with atomistic molecular（MD）and mesoscopic dynamics（MesoDyn）simulations.The Flory-Huggins parameters determined from the cohesive energy densities and the radial distribution functions of the inter-molecular carbon atomic pairs of PP-PP,PA11-PA11 and PP-PA11 chains in the blends suggested that PP/PA11 90/10 blends were more miscible.As a further proof,the MesoDyn program was used to simulate the phase separation dynamics of the blends at the mesoscopic level.Interaction parameters obtained from atomistic simulations along with other structure-dependent（monomer number and length,characteristic ratio）parameters were subsequently changed into input parameters for the mesoscopic simulations.The mesoscopic morphology simulated by MesoDyn further supported the MD simulations results.