含氟高分子材料在浓硫酸介质中的耐腐蚀性机理  

Corrosion Resistance Mechanism of Fluorinated Polymer Materials in Concentrated Sulfuric Acid Medium

作　　者：宗韧哲 王志强[1] 蔡尚脉 陆铭 仝毅[1] 黄风雷[1,2] Zong Renzhe;Wang Zhiqiang;Cai Shangmai;Lu Ming;Tong Yi;Huang Fenglei(State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China;Yangtze Delta Region Academy of Beijing Institute of Technology,Jiaxing 314019,China;Beijing Research and Design Institute of Rubber Industry Co.,Ltd.,Beijing 100143,China)

机构地区：[1]北京理工大学爆炸科学与技术国家重点实验室,北京100081 [2]北京理工大学长三角研究院,浙江嘉兴314019 [3]北京橡胶工业研究设计院有限公司,北京100143

出　　处：《工程塑料应用》2023年第10期132-139,共8页Engineering Plastics Application

摘　　要：为明晰含氟高分子材料的耐腐蚀性机理,采用分子动力学方法研究了浓硫酸溶液在聚四氟乙烯(PTFE)与聚全氟乙丙烯(FEP)中的扩散行为,计算了浓硫酸溶液中氢离子在不同共混体系模型中的均方位移与扩散系数,并通过PTFE和FEP在不同温度和时间下的浓硫酸浸泡实验,采用质量损失率、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)和力学性能分析方法对实验前后的试样进行表征。结果表明,在分子动力学模拟中,浓硫酸中的氢离子在PTFE中的均方位移和扩散系数更大,扩散更剧烈。在常温浸泡实验后,PTFE和FEP都出现了轻微的渗透腐蚀现象,PTFE孔洞上方相连处出现断缺,FEP表面则出现孔洞,两者的质量和力学性能都略微减少。在高温浸泡实验后,PTFE和FEP的孔洞直径均略微增加,质量损失率分别为0.113%和0.091%,断裂伸长率分别下降了34%和9%,但两者的化学结构基本无变化,均体现出了良好的耐腐蚀性,且FEP的耐腐蚀性能表现更优异。In order to clarify the corrosion resistance mechanism of fluorinated polymer materials,molecular dynamics method was used to study the diffusion behavior of concentrated sulfuric acid solution in polytetrafluoroethylene(PTFE)and fluorinated ethylene propylene(FEP).The mean square displacement and diffusion coefficient of hydrogen ions in concentrated sulfuric acid solution were calculated in different blend system models.Through concentrated sulfuric acid immersion experiments of PTFE and FEP at different temperatures and times,the samples before and after the experiment were characterized using mass loss rate,scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and mechanical property analysis methods.The results indicate that in molecular dynamics simulation,the mean square displacement and diffusion coefficient of hydrogen ions in concentrated sulfuric acid in PTFE are larger,and the diffusion is more intense.After the immersion experiment at room temperature,both PTFE and FEP show slight infiltration corrosion,with fractures at the connection above the PTFE holes and holes on the surface of FEP,the mass and mechanical properties of both decrease slightly.After the immersion experiment at high temperature,the holes diameters of PTFE and FEP both slightly increase,and the mass loss rate is 0.113%and 0.091%,respectively.The elongation at break decreases by 34%and 9%,respectively.However,the chemical structures of PTFE and FEP remain basically unchanged,demonstrating good corrosion resistance,and FEP performs better in corrosion resistance.

关 键 词：聚四氟乙烯 聚全氟乙丙烯 耐腐蚀性 浓硫酸 分子动力学 

分 类 号：TQ325.4[化学工程—合成树脂塑料工业]