The Effect of Elastomer Compounding for Improved Sealing Performance and Long-Term Durability of O-Rings in Harsh Chemical Environments

The appropriate selection of elastomers to ensure the reliability of sealing systems in corrosive environments is a critical challenge in polymer engineering. This research aims to comprehensively evaluate the effect of the chemical composition of four elastomer families (NBR, EPDM, FKM, and FFKM) on the physical and mechanical stability of O-rings exposed to hydrocarbon environments and ۹۸% sulfuric acid at ۹۰°C. Experiments were conducted at intervals of ۱۰۰, ۵۰۰, and ۱۰۰۰ hours, and parameters such as volume changes, tensile strength, hardness, Young’s modulus, and structural changes were evaluated using FTIR and SEM techniques. The research findings showed that the NBR elastomer, due to the high reactivity of its backbone chains, undergoes severe volume swelling (up to ۶۵.۸% in hydrocarbon environments) and a critical drop in tensile strength (۷۲.۳%), resulting from oxidation and chain scission. In contrast, the FFKM polymer, utilizing highly stable C-F bonds, exhibited the lowest volume change (less than ۱.۲%) and complete retention of mechanical and morphological properties. Spectroscopic and microscopic analyses confirmed that the stability of FFKM is due to its resistance to solvent penetration and lack of reaction with acidic protons. The results of this study emphasize that to prevent sudden failures and ensure long-term operational life in extremely harsh environmental conditions, the use of perfluoro elastomers (FFKM) is essential due to their extraordinary structural and mechanical stability.

کلیدواژه ها:

Elastomer ، O-ring ، Chemical stability ، Corrosive environments ، FFKM ، Polymer degradation ، Industrial sealing