Ⅳ型储氢瓶PA6内胆材料氢渗透性能和老化机制的分子动力学模拟研究

doi:10.11949/0438-1157.20250595

摘要/Abstract

摘要：

氢渗透是Ⅳ型储氢瓶安全服役的重要挑战，往往会加重聚合物内胆的损伤以及氢气的渗漏。针对Ⅳ型储氢瓶聚合物内胆氢渗透性能优化需求，以聚酰胺6（PA6）为研究对象，通过分子模拟，系统揭示了温度、压力、热氧老化及氧化石墨烯共聚改性对PA6氢渗透机制的影响规律。结果表明：温度升高（263K-353 K）使PA6氢渗透系数增大38.44%-162.90%，这是因为温度对扩散系数的增大作用占主导；压力升高（30MPa-60 MPa）通过减小自由体积（占主导作用），增大分子无规则速度，导致扩散系数出现下降的趋势，但一定的压力后，对分子无规则速度的增大作用占主导，扩散系数出现上升的趋势。热氧老化导致PA6主链断裂及极性基团生成，导致扩散系数最高增大125.5%，渗透系数最高增大114.09%。氧化石墨烯共聚改性通过延长氢分子扩散路径与降低自由体积，使扩散系数最高降低39.43%。

关键词: Ⅳ型储氢瓶, 聚合物, 渗透, 动力学, 数值模拟

Abstract:

Hydrogen permeation is a significant challenge for the safe operation of type Ⅳ hydrogen storage bottles, often causing damage to the polymer liner and hydrogen leakage. To address the optimization requirements for the hydrogen permeation performance of the polymer liner in type Ⅳ hydrogen storage bottles, using polyamide 6 (PA6) as the research object, through molecular simulation, the influence laws of temperature, pressure, thermal oxidation aging, and graphene oxide copolymer modification on the hydrogen permeation mechanism of PA6 were systematically revealed. The results show that an increase in temperature (263K - 353K) causes the hydrogen permeation coefficient of PA6 to increase by 38.44% - 162.90%, because the effect of temperature on the increase of the diffusion coefficient is dominant; an increase in pressure (30 MPa - 60 MPa) reduces the free volume (dominant role), increases the molecular irregular velocity, and leads to a downward trend in the diffusion coefficient, but after a certain pressure, the increase in the molecular irregular velocity dominates, and the diffusion coefficient shows an upward trend. Thermal oxidation aging leads to the breakage of the PA6 main chain and the generation of polar groups, resulting in the highest increase of the diffusion coefficient by 125.5% and the highest increase of the permeation coefficient by 114.09%. Graphene oxide copolymer modification reduces the diffusion coefficient by up to 39.43% by extending the hydrogen molecule diffusion path and reducing the free volume.

Key words: Type Ⅳ hydrogen storage cylinder, polymers, permeation, kinetics, numerical simulation

中图分类号:

TK91

牛棒棒, 李岩, 董楚峰, 李翔. Ⅳ型储氢瓶PA6内胆材料氢渗透性能和老化机制的分子动力学模拟研究[J]. 化工学报, DOI: 10.11949/0438-1157.20250595.

Bangbang NIU, Yan LI, Chufeng DONG, Xiang LI. Molecular Dynamics Simulation Study on Hydrogen Permeation Performance and Aging Mechanism of PA6 Inner Liner Material for Type Ⅳ Hydrogen Storage Cylinders[J]. CIESC Journal, DOI: 10.11949/0438-1157.20250595.

图/表 31

图1 分子模型

Fig.1 Molecular model

图2 晶胞模型

Fig.2 Cell models

图3 几何优化结果

Fig.3 Results of Geometric optimization

图4 降解后的产物

Fig.4 Degradation products

图5 老化后的晶胞模型

Fig.5 Aged cell model

图6 能量变化

Fig.6 Energy change

图7 共聚改性后的模型

Fig.7 Model after copolymerization modification

图8 退火时的能量变化

Fig.8 Energy changes during annealing process

图9 退火时的温度变化

Fig.9 Temperature changes during annealing process

图10 晶胞模型密度变化

Fig.10 Changes of cell model

图11 扩散系数实验结果

Fig.11 Experimental results of diffusion coefficient

图12 等温吸附曲线

Fig.12 Isothermal adsorption curve

图13 溶解度系数

Fig.13 Solubility coefficient

图14 不同温度下的均方位移图

Fig.14 MSD diagrams at different temperatures

图15 不同压力下的均方位移图

Fig.15 MSD diagrams under different pressures

表1 不同压力与温度下的扩散系数（10-4cm2/s）

Table1 Diffusion coefficients under different pressures and temperatures（10-4cm2/s）

T/K	p/ MPa
T/K	30	41.6	52	60
263	0.5426	0.3930	0.4251	0.4439
298	0.8751	0.8479	0.6352	0.7219
323	1.1945	1.0687	1.0520	1.0513
353	1.4750	1.2286	1.3103	1.3548

表2 不同压力与温度下的渗透系数（10-11 cm3（STP）·cm/（cm2·Pa·s））

Table2 Permeability coefficients under different pressures and temperatures（10-11 cm3（STP）·cm/（cm2·Pa·s））

T/K	p/ MPa
T/K	30	41.6	52	60
263	2.5601	1.8542	2.0057	2.0944
298	3.8253	3.7064	2.7766	3.1556
323	4.9388	4.4187	4.3496	4.3467
353	5.5824	4.8748	5.1989	5.3755

图16 老化模型等温吸附曲线

Fig.16 Isothermal adsorption curve of the aging model

图17 老化模型的溶解度系数

Fig.17 Solubility coefficient of the aging model

图18 老化模型的均方位移图

Fig.18 MSD diagrams of the aging model

表3 老化模型的扩散系数（10-4cm2/s）

Table3 Diffusion coefficient of the aging model（10-4cm2/s）

T/K	p/ MPa
T/K	30	41.6	52	60
263	0.6420	0.8862	0.8630	0.7655
298	1.0518	1.1115	1.0353	0.9881
323	1.2860	1.1827	1.1476	1.1147
353	1.8225	1.7348	1.6141	1.4575

图19 初始模型与热氧老化模型均方位移图对比

Fig.19 The comparison of the initial model and the thermal oxidation aging model in terms of the MSD

表4 老化模型与初始模型扩散系数对比

TAble.4 Comparison of diffusion coefficients between the aging model and the initial model

T/K	p/ MPa
T/K	30	41.6	52	60
263	18.32%	125.50%	103.31%	72.45%
298	20.19%	31.09%	62.99%	36.87%
323	7.66%	10.67%	9.09%	6.03%
353	23.56%	41.20%	23.19%	7.58%

表5 老化模型的渗透系数（10-11 cm3（STP）·cm/（cm2·Pa·s））

Table5 Permeability coefficient of the aging model（10-11 cm3（STP）·cm/（cm2·Pa·s））

T/K	p/ MPa
T/K	30	41.6	52	60
263	2.8759	3.9698	3.8658	3.4291
298	4.3781	4.6266	4.3094	4.1129
323	5.2361	4.8155	4.6726	4.5386
353	7.1271	6.7842	6.3121	5.6997

图20 老化模型与初始模型渗透系数对比

Fig.20 Comparison of permeability coefficients between the aging model and the initial model

表6 老化模型与初始模型渗透系数对比

Table6 Comparison of permeability coefficients between the aging model and the initial model

T/K	p/ MPa
T/K	30	41.6	52	60
263	12.34%	114.09%	92.74%	63.73%
298	14.14%	24.83%	55.20%	30.34%
323	6.02%	8.98%	7.43%	4.41%
353	21.78%	39.17%	21.41%	6.03%

图21 改性模型的均方位移图

Fig.21 MSD diagrams of the modified model

表7 改性模型的扩散系数（10-4cm2/s）

Table7 Diffusion coefficient of the modified model（10-4cm2/s）

T/K	p/ MPa
T/K	30	41.6	52	60
263	0.4928	0.3789	0.3919	0.4060
298	0.6933	0.5573	0.5607	0.6856
323	0.8337	0.6473	0.7995	0.8374
353	1.2025	1.0085	0.9359	0.9817

图22 初始模型与改性模型均方位移图对比

Fig.22 Comparison of the initial model and the modified model in terms of the MSD

图23 改性模型与初始模型渗透系数对比

Fig.23 Comparison of permeability coefficients between the modified model and the initial model

表8 改性模型与初始模型扩散系数对比

TAble.8 Comparison of diffusion coefficients between the modified model and the initial model

T/K	p/ MPa
T/K	30	41.6	52	60
263	9.18%	3.59%	7.81%	8.54%
298	20.77%	34.27%	11.73%	5.03%
323	30.21%	39.43%	24.00%	20.35%
353	18.47%	17.91%	28.57%	27.54%

参考文献 34

[1]	徐君臣, 银建中. 纤维缠绕复合材料气瓶研究进展[J]. 应用科技, 2012, 39(4):64-71.
	Xu J C, Yin J Z. Progress in filament-wound composite gas cylinders[J]. Applied Science and Technology, 2012, 39(4): 64-71.
[2]	Al-Juboori O, Sher F, Hazafa A, et al. The effect of variable operating parameters for hydrocarbon fuel formation from CO₂ by molten salts electrolysis[J]. Journal of CO₂ Utilization, 2020, 40: 101193.
[3]	凌文, 李全生, 张凯. 我国氢能产业发展战略研究[J]. 中国工程科学, 2022, 24(3): 80-88.
	Ling W, Li Q S, Zhang K. Development strategy of hydrogen energy industry in China[J]. Strategic Study of CAE, 2022, 24(3): 80-88.
[4]	TANG H Y, WU Y B, XIONG L, et al. Research on quality assurance system of high pressure hydrogen storage cylinder for hydrogen fuel cell electric vehicle[J]. China Auto, 2020(12): 25-29.
[5]	LIU C W, PEI Y B, HAN H, et al. Research status and development trend of hydrogen energy industry chain and the storage and transportation technologies[J]. Oil & Gas Storage and Transportation, 2022, 41(5): 498-514.
[6]	Su Y, Lv H, Zhou W, et al. Review of the Hydrogen Permeability of the Liner Material of Type Ⅳ On-Board Hydrogen Storage Tank[J]. World Electric Vehicle Journal, 2021, 12(3): 130.
[7]	Kanesugi H, Ohyama K, Fujiwara H, et al. High-pressure hydrogen permeability model for crystalline polymers[J]. International Journal of Hydrogen Energy, 2023, 48(2): 723-739.
[8]	邱玥, 周苏洋, 顾伟, 等. "碳达峰、碳中和"目标下混氢天然气技术应用前景分析[J]. 中国电机工程学报, 2022, 42(4): 1301-1321.
	Qiu Y, Zhou S Y, Gu W, et al. Application prospect analysis of hydrogen enriched compressed natural gas technologies under the target of carbon emission peak and carbon neutrality[J]. Proceedings of the CSEE, 2022, 42(4): 1301-1321.
[9]	曹军文, 覃祥富, 耿嘎, 等. 氢气储运技术的发展现状与展望[J]. 石油学报(石油加工), 2021, 37(6): 1461-1478.
	Cao J W, Qin X F, Geng G, et al. Current status and prospects of hydrogen storage and transportation technology[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2021, 37(6): 1461-1478.
[10]	Kane M. PERMEABILITY, SOLUBILITY, AND INTERACTION OF HYDROGEN IN POLYMERS- AN ASSESSMENT OF MATERIALS FOR HYDROGEN TRANSPORT [R]. South Carolina: Aiken, 2008.
[11]	郭淑芬, 吕家龙, 高智惠, 等. 有关非金属内胆全缠绕储氢气瓶渗透参数的探讨[J]. 低温与特气, 2020, 38(5): 16-18.
	Guo S F, Lü J L, Gao Z H, et al. Discussion on permeability brameters of fully-wrapped hydrogen storage cylinder with non-metal liner[J]. Low Temperature and Specialty Gases, 2020, 38(5): 16-18.
[12]	Fang Q, Ji D M. Molecular simulation of hydrogen permeation behavior in liner polymer materials of Type IV hydrogen storage vessels[J]. Materials Today Communications, 2023, 35: 106302.
[13]	Sun Y, Lv H, Zhou W, et al. Research on hydrogen permeability of polyamide 6 as the liner material for type IV hydrogen storage tank[J]. International Journal of Hydrogen Energy, 2020, 45(46): 24980-24990.
[14]	Naito Y, Mizoguchi K, Terada K, et al. The effect of pressure on gas permeation through semicrystalline polymers above the glass transition temperature[J]. Journal of Polymer Science Part B: Polymer Physics, 1991, 29(4): 457-462.
[15]	Dong C, Liu Y, Li J, et al. Hydrogen Permeability of Polyamide 6 Used as Liner Material for Type IV On-Board Hydrogen Storage Cylinders[J]. Polymers, 2023, 15(18):3715.
[16]	Fujiwara H, Ono H, Ohyama K, et al. Hydrogen permeation under high pressure conditions and the destruction of exposed polyethylene-property of polymeric materials for high-pressure hydrogen devices (2)-[J]. International Journal of Hydrogen Energy, 2021, 46(21): 11832-11848.
[17]	Wang X L, Tian M M, Chen X D, et al. Advances on materials design and manufacture technology of plastic liner of type Ⅳ hydrogen storage vessel[J]. International Journal of Hydrogen Energy, 2022, 47(13): 8382-8408.
[18]	Duncan T V. Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors[J]. Journal of Colloid and Interface Science, 2011, 363(1): 1-24.
[19]	Kunz D A, Schmid J, Feicht P, et al. Clay-based nanocomposite coating for flexible optoelectronics applying commercial polymers[J]. ACS Nano, 2013, 7(5): 4275-4280.
[20]	DeRocher J P, Gettelfinger B T, Wang J S, et al. Barrier membranes with different sizes of aligned flakes[J]. Journal of Membrane Science, 2005, 254(1/2): 21-30.
[21]	Flaconneche B, Martin J, Klopffer M H. Permeability, diffusion and solubility of gases in polyethylene, polyamide 11 and poly (vinylidene fluoride)[J]. Oil & Gas Science and Technology, 56(3): 261-278.
[22]	熊耀强, 吴平, 赵建平. Ⅳ型储氢气瓶内衬材料的氢渗透行为分子动力学模拟[J]. 压力容器, 2023, 40(7): 19-28.
	Xiong Y Q, Wu P, Zhao J P. Molecular dynamics simulations on hydrogen permeation of modified polymer liner for type Ⅳ storage vessels[J]. Pressure Vessel Technology, 2023, 40(7): 19-28.
[23]	Kamiya Y, Naito Y, Terada K, et al. Volumetric properties and interaction parameters of dissolved gases in poly(dimethylsiloxane) and polyethylene[J]. Macromolecules, 2000, 33(8): 3111-3119.
[24]	Boyd R H, Pant P K. Molecular packing and diffusion in polyisobutylene[J]. Macromolecules, 1991, 24(23): 6325-6331.
[25]	李兰艳, 李光吉, 李超, 等. 尼龙6在热氧老化中的性能与结构变化[J]. 塑料科技, 2009, 37(12): 36-41.
	Li L Y, Li G J, Li C, et al. Changes in the properties and structures of PA6 during the course of thermal-oxidative aging[J]. Plastics Science and Technology, 2009, 37(12): 36-41.
[26]	Zhao X W, Li X H, Ye L, et al. Stress–thermooxidative aging behavior of polyamide 6[J]. Journal of applied polymer science, 2013, 129(3): 1193-1201.
[27]	陈琛, 韩燚, 孙海燕, 等. 花状氧化石墨烯原位展开共聚聚酰胺6及其功能纤维[J]. 纺织学报, 2023, 44(1):47-55.
	Chen C, Han Y, Sun H Y, et al. Flower-shaped graphene oxide in situ unfolding polyamide-6 and functional fibers thereof[J]. Journal of Textile Research, 2023, 44(1): 47-55.
[28]	何曼君, 张红东, 陈维孝, 等. 高分子物理第三版[M]. 上海: 复旦大学出版社, 2008.
	He M J, Zhang H D, Chen W X, et al. Polymer Physics Third edition[M]. Shanghai: Fudan University Press, 2008.
[29]	Mozaffari F, Eslami H, Moghadasi J. Molecular dynamics simulation of diffusion and permeation of gases in polystyrene[J]. Polymer, 2010, 51(1): 300-307.
[30]	李顺阳. 储氢气瓶内衬异质界面连接强度和氢透性分子模拟[D]. 太原: 太原科技大学, 2023.
	Li S Y. Molecular simulation of bonding strength and hydrogen permeability of heterogeneous interface in hydrogen storage bottle lining[D]. Taiyuan: Taiyuan University of Science and Technology, 2023.
[31]	王蓓娣. 氧化石墨烯的功能化改性及应用研究[D]. 上海: 复旦大学, 2012.
	Wang B D. Study on functional modification and application of graphene oxide[D]. Shanghai: Fudan University, 2012.
[32]	张学敏, 翟丽珍, 李厚补, 等. 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[J]. 中国塑料, 2024, 38(8): 62-68.
	Zhang X M, Zhai L Z, Li H B, et al. Molecular simulation of hydrogen permeation behavior of polyamide 6 liner material for type Ⅳ hydrogen storage cylinder[J]. China Plastics, 2024, 38(8): 62-68.
[33]	Xiang J H, Zeng F G, Liang H Z, et al. Molecular simulation of the CH₄/CO₂/H₂O adsorption onto the molecular structure of coal[J]. Science China Earth Sciences, 2014, 57(8): 1749-1759.
[34]	Yi Y, Bi P, Zhao X F, et al. Molecular dynamics simulation of diffusion of hydrogen and its isotopic molecule in polystyrene[J]. Journal of Polymer Research, 2018, 25(2): 43.