Influence of HFO refrigerants on the viscoelastic behavior of elastomers.

The hydrofluoroolefines (HFO) have been introduced within the last years as new generation of refrigerants having a significantly lower Global Warming Potential. Compared to the state-of-the-art fluids within the class of hydrofluorocarbons (HFC), the HFO molecules are unsaturated, consisting of double bonded carbon atoms. The difference in the chemical structure may cause different interaction with polymers, especially elastomers, which tend to swell when exposed to certain refrigerants. In this study, the influence of modern refrigerants on the viscoelastic behavior of elastomers is analyzed. The investigated refrigerants are two state-of-the-art fluids, namely R245fa and R134A, as well as three next-generation refrigerants R1233zd-E, R1234yf and R1234ze-E. The investigated polymers comprise ethylene-propylene-diene rubber, fluororubber, chlorobutadiene rubber and nitrile butadiene rubber. From this analysis it can be concluded, that the investigation of the viscoelastic behavior gives meaningful insights to better understand the fluid-polymer interaction and thus helps to evaluate the material compatibility.