GAP/N-100交联体系力学和热解机理的MD模拟

MD simulation of mechanics and pyrolysis mechanismof GAP/N-100 crosslinking system

为探究聚叠氮缩水甘油醚(GAP)与多异氰酸酯(N-100)交联形成三维网状聚合物的力学性能、热分解机理和主要产物信息,采用perl语言结合分子动力学模拟软件编写了能实现GAP与N-100交联的脚本,建立了不同交联度的GAP/N-100分子模型,并预测了不同交联体系的力学性能,采用反应分子动力学对热解机理和产物进行了模拟。结果表明:通过自编脚本可以得到一系列不同交联度的交联模型,最终交联度为96.7%;随着交联度的增大,GAP/N-100体系的杨氏模量、剪切模量和体积模量均逐渐提高。GAP/N-100交联体系热解的初始分解机理为叠氮基团的脱落以及碳骨架的分解,热解反应的活化能Ea为13.411 kJ/mol,指前因子A为0.099 1/ps-1,热解的主要产物有N2、H_(2)、H_(2)O以及NH3,主要的中间产物为CH_(2)O。

In order to investigate the mechanical properties,thermal decomposition mechanism and main product information of a three-dimensional reticulated polymer formed by crosslinking multi-functional isocyanate(N-100)with glycidyl azide polymer(GAP),this work firstly used the perl language in combination with molecular dynamics simulation software to write a script that can realize the crosslinking of GAP and N-100,established models of GAP/N-100 with different crosslinking conversions and predicted the mechanical properties of crosslinked system,and then the reactive molecular dynamics was used to simulate the pyrolysis mechanism and product information.The results demonstrated thata series of crosslinking models with different crosslinking conversions can be obtained by the self-programmed script,and the final crosslinking conversion is 96.7%;with the increase of crosslinking conversion,the young’s modulus,shear modulus,and bulk modulus of the GAP/N-100 system all gradually enhanced.Regarding the initial decomposition mechanism during the pyrolysis of the GAP/N-100 system,it involved the shedding of azide groups and the decomposition of the carbon skeleton.The activation energy(E a)for the pyrolysis reaction was found to be 13.411 kJ/mol,and the pre-exponential factor A was calculated to be 0.0991/ps-1.The primary products of the pyrolysis were N 2,H 2,H 2O,and NH 3,with the main intermediate product being CH 2O.