“…The asymmetric hollow fibers allowing to obtain gas target components find applications in the aerospace industry, storage of fruit and vegetable products in a controlled gas environment, breathing mixture creation in medicine, replacing oxygen pillows, patients treatment by interval hypoxia (including "mountain air"), hydrogen separation after methane conversion, helium extraction from natural gas, regeneration of catalysts, etc. The polyphenylene oxide (PPO) choice as a modifiable membrane material is related to the increased interest in membrane technology, including direct industrial applications [8][9][10][11][12][13][14]. PPO is a glassy polymer with glass transition temperature ranging from 212 to 218 •C.…”