摘要
分子动力学模拟是研究分子结构与性能的一种十分重要且有效的方法。为研究聚酰亚胺(PI)分子的微观降解机理,利用分子动力学软件,采用基于密度泛函理论(DFT)的量子力学程序对聚合度为5的均苯型聚酰亚胺分子进行了降解模拟。通过对Mulliken重叠布居数及PI分子降解过程的计算与模拟,发现PI分子主链结构上的醚键(C—O—C)、酰亚胺环(C—N—C)上的C—N键较弱,在PI分子受热过程中容易断裂,造成PI分子聚合度降低;醚键断裂和酰亚胺环开环可能导致PI分子有2种不同的降解路径,其最终降解产物主要有H2O、NO、CO、CO2及NO2等气体。该研究成果有助于在原子水平对PI的结构与性能进行研究,从而更深入认识PI分子热降解的微观机理。
Molecular dynamics simulation method is an important and effective method to investigate the structure and performance of molecule.Based on the quantum mechanics of density functional theory,the molecular dynamics software was used to study the microcosmic degradation mechanism of polyimide with 5 monomers.Through the calculation of Mulliken＇s overlap population and simulation of pyrolysis process of PI,it is shown that the bond energy of ether bond（C-O-C） on the main chain of PI and the C-N bond on the imide ring is weak,which is easy to break during the heating process.There are two probable pyrolysis paths of PI molecule because of the rupture of ether bond（C-O-C） and C-N bond.The final products mainly include H2O,NO,CO,CO2,NO2,and so on.It is helpful to exploring the structure and property of PI film based on the atomic level,so that the mechanism of thermal degradation can be understood more profoundly.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2012年第10期2707-2713,共7页
High Voltage Engineering
基金
国家自然科学基金(51177136)
新世纪优秀人才支持计划(NCET-07-0718)~~
关键词
聚酰亚胺(PI)
分子动力学模拟
热解
微观机理
聚合度
分子链断裂
polyimide（PI）
molecular dynamic simulation
pyrolysis
microscopic mechanism
degree of polymerization
decomposition of molecular chain
