IV型储氢气瓶内衬材料聚酰胺6氢渗透行为的分子模拟研究
Molecular simulation of hydrogen permeation behavior of polyamide 6 liner material for type IV hydrogen storage cylinder
张学敏 1翟丽珍 1李厚补 2齐国权 2黄尚彬 1张冬娜 2杨志锋 3张晓宇3
作者信息
- 1. 长安大学材料科学与工程学院,西安 710064
- 2. 中国石油集团工程材料研究院有限公司,石油管材及装备材料服役行为与结构安全国家重点实验室,西安 710077
- 3. 宝鸡天联汇通复合材料有限公司,陕西 宝鸡 712013
- 折叠
摘要
采用分子模拟方法,在不同温度(30、40、60、80℃)和压力(82、87.5、98、103 MPa)条件下,研究氢气在聚合物材料聚酰胺6(PA6)中的渗透性,并分析了氢气的渗透机理.结果表明,温度升高时,吸附热和自由体积分数逐渐增加,热运动加剧,分子运动空间增大,氢气在PA6中的溶解度系数、扩散系数以及渗透系数均呈增大趋势.在压力为103 MPa时,升高温度对渗透系数的影响最大,增加了88.3%.随着压力增大,氢气与PA6分子链之间的相互作用减小,自由体积分数减小,所以氢气在PA6中的溶解度系数、扩散系数以及渗透系数均呈下降趋势.在温度为60℃时,压力对渗透系数影响最显著,降低了38.6%.氢气在PA6中的渗透机理包括在低势能区的聚集性吸附过程,和在自由体积处形成的空穴内振动-空穴间跃迁的扩散过程,温度升高时,氢气分子运动变得活跃,有更多的空穴间跳跃次数,压力升高时,变化相反.
Abstract
In this work,the permeability of hydrogen in the polymer polyamide 6(PA6)was studied by molecular simula-tion methods at different temperatures(30,40,60 and 80℃)and pressures(82,87.5,98 and 103 MPa).Meanwhile,the permeability mechanism of hydrogen was analyzed.The results indicated that as the temperature increases,the ad-sorption heat and free volume fraction gradually increases,the thermal motion intensifies and the molecular motion space increases.And the solubility,diffusion and permeability coefficient of hydrogen in PA6 all increase.At a pressure of 103 MPa,increasing the temperature has the greatest impact on the permeability coefficient,which increases by 88.3%.With the increase of pressure,the interaction between hydrogen and PA6 molecular chains decreases and the free volume fraction decreases,so the solubility,diffusion and permeability coefficient of hydrogen in PA6 all show a downward trend.When the temperature was 60℃,the pressure had the most significant influence on the permeability coefficient,which de-creased by 38.6%.The permeation mechanism of hydrogen in PA6 includes the aggregation adsorption process in the low potential energy region and the diffusion process of intra-cavity vibration-inter-cavity transition formed in the free vol-ume.With the increase of temperature,the movement of hydrogen molecules becomes active and there are more inter-cavity jumps.When the pressure increases,the change is opposite.
关键词
聚酰胺6/氢气/扩散/吸附/渗透/分子模拟Key words
polyamide 6/hydrogen/diffusion/adsorption/permeation/molecular simulation引用本文复制引用
基金项目
国家自然科学基金面上项目(52274069)
陕西省重点研发计划(2023-YBGY-177)
大学生创新创业训练计划项目(X202210710582)
出版年
2024
国家科技期刊平台
NSTL
万方数据