摘要
采用多尺度模拟与实验相结合的方法,分析了UHMWPE/HDPE/LP共混体系的相容性和微观相互作用机制.基于分子动力学(MD)模拟和耗散粒子动力学(DPD)模拟研究了高密度聚乙烯(HDPE)对超高分子量聚乙烯(UHMWPE)与白油(LP)共混体系相容性的影响,对MD模拟得到的结合能和径向分布函数及DPD模拟得到的等密度进行分析.模拟结果表明,UHMWPE/HDPE/LP体系的结合能为8 978.23 kJ/mol,大于UHMWPE/LP体系的结合能(8 013.39 kJ/mol);UHMWPE/HDPE/LP体系中不同类分子间C—C原子对的g(r)高于UHMWPE/LP体系中不同类分子间C—C原子对的g(r),并且,特征峰均在5 Å处出现,范德华作用为分子间的主要相互作用形式;DPD模拟的结果表明,UHMWPE/HDPE/LP体系中分散相的相畴尺寸较小,2种体系均没有相分离的情况.上述结果表明,与UHMWPE/LP体系相比,UHMWPE/HDPE/LP体系的相容性得到显著改善.为证明模拟结果的准确性,对UHMWPE/HDPE/LP原料采用熔融共混方法制备了2种样品,并且,采用扫描电镜(SEM)对样品进行检测,分析了HDPE对共混材料微观形貌的影响,实验结果与模拟结论匹配性较好.
Abstract
The compatibility and micro-interaction mechanism of UHMWPE/HDPE/LP blends were studied by using multi-scale simulation and experiment.The effect of high density polyethylene(HDPE)on the compatibility of ultra high molecular weight polyethylene(UHMWPE)and white oil(LP)blends were studied based on molecular dynamics(MD)simulation and dissipative particle dynamics(DPD)simulation.The binding energy and radial distribution function obtained by MD simulation and the isodensity obtained by DPD simulation were analyzed.The results showed that the binding energy of UHMWPE/HDPE/LP system was 8 978.23 kJ/mol,which was higher than that of UHMWPE/LP system(8 013.39 kJ/mol).The g(r)of C—C atom pairs between different molecules in UHMWPE/HDPE/LP system was higher than that of C—C atom pairs between different molecules in UHMWPE/LP system,and the characteristic peaks all appeared at 5 Å.The van der Waals interaction dominated the intermolecular interaction shape.The results of DPD simulation showed that the phase domain size of the dispersed phase in UHMWPE/HDPE/LP system was small,and there was no phase separation in both systems.The above results showed that the compatibility of UHMWPE/HDPE/LP system was improved compared with UHMWPE/LP system.In order to verify the accuracy of the simulation results,two samples of UHMWPE/HDPE/LP raw materials were prepared by melt blending and scanning electron microscopy(SEM)was used to detect the samples.The influence of HDPE on the microstructure of the blended materials was analyzed and the experimental results were well matched with the simulation conclusions.
维普
万方数据