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

发布时间：2018-03-29 06:07

本文选题：无定形聚合物　切入点：分子动力学　出处：《塑料科技》2017年12期

【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。
[Abstract]:In order to study the effect of mixing ratio and temperature on the uniaxial tensile deformation behavior of amorphous polymer, a coarse grained polyvinyl alcohol model was used. The molecular dynamics software lammps was used to simulate the uniaxial tensile process of mixed systems with different chain lengths and different proportions at different temperatures. The establishment of the mixed system made the simulation tend to the polydispersity of real polymers. Four typical deformation stages (elastic deformation, The stress-strain curves of yield, strain softening and strain strengthening) can be obtained: the increase of long chain leads to unwinding and reorientation, which leads to obvious strain strengthening, and when the short chain increases and the temperature decreases, the phenomenon of sudden fracture appears more easily; Mixing ratio has little effect on elastic deformation, yield and strain softening, but has significant effect on strain strengthening. The smaller the mixing ratio is, the longer the chain is, the more obvious the strain strengthening stage is and the longer the time is.
【作者单位】：太原理工大学机械工程学院;太原理工大学煤矿综采装备山西省重点实验室;
【基金】：国家青年科学基金项目(51303123)
【分类号】：O631.21

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