混合比、温度对无定形聚合物拉伸形变影响的分子动力学模拟  

Molecular Dynamics Simulation for the Effect of Mixing Ratio and Temperature on Tensile Deformation of Amorphous Polymers

作　　者：李红[1,2] 王飞 李彦周 李星宇[1,2] 刘龙攀 陈占春 

机构地区：[1]太原理工大学机械工程学院,山西太原030024 [2]太原理工大学煤矿综采装备山西省重点实验室,山西太原030024

出　　处：《塑料科技》2017年第12期38-42,共5页Plastics Science and Technology

基　　金：国家青年科学基金项目(51303123)

摘　　要：为研究混合比、温度对无定形聚合物单轴拉伸形变行为的影响,采用粗粒化聚乙烯醇模型,应用分子动力学软件lammps模拟不同链长按不同比例组成的混合体系在不同温度下的单轴拉伸过程。混合体系的建立使得模拟趋向实际聚合物的多分散性。分析仿真得出的4个典型变形阶段(弹性变形、屈服、应变软化、应变强化)的应力应变曲线可得出:长链增多引起解缠、重新取向困难,导致应变强化显著,而当短链增多且温度降低时,突然断裂的现象也越容易出现;混合比对弹性变形、屈服及应变软化几乎没有影响,而对应变强化有显著的影响,混合比越小,较长的链越多,应变强化阶段越明显,历经的时间越长。To study the effect of mixing ratio and temperature on tensile deformation of amorphous polymers, a coarse grained PVA model was used and the molecular dynamics software lammps was used to simulate the uniaxial tensile process of the mixed system with different chain lengths and different proportions. The establishment of the mixed system makes the simulation tend to the polydispersity of the actual polymer. The stress-strain curves of four typical deformation stages（elastic deformation, yield, strain softening, strain hardening） were obtained by analyzing the simulation as follows： the increase in the length of the strand leads to the difficulty of unwrapping and reorientation, leading to strain hardening, while the phenomenon of sudden fracture is more likely to occur when the short chain increases and the temperature decreases. The mixing ratio has almost no effect on elastic deformation, yield and strain softening, but has a significant effect on strain hardening. The smaller the mixing ratio is, the longer the chain is; the longer the strain hardening stage is, and the longer the strain duration is.

关 键 词：无定形聚合物 分子动力学 粗粒化模型 混合体系 力学行为 

分 类 号：O631.21[理学—高分子化学]