Copolymers with polyamide blocks and flexible blocks||Copolymers with polyamide blocks and flexible blocks

The present invention relates to a thermoplastic copolymer containing semi-crystalline polyamide blocks and flexible blocks, wherein: - the semi-crystalline polyamide blocks contain from 30 to 75% by weight, preferably from 30 to 70% by weight of aliphatic dicarboxylic acid and/or diamine comprising at least 36 carbon atoms, relative to the total weight of polyamide blocks, the repeating units of the polyamide blocks of the copolymer having a mean carbon content of greater than or equal to 7, - the flexible blocks comprise blocks derived from polyethylene glycol and, - the weight proportion of the polyamide blocks is of from 15 to 60% by weight relative to the total weight of the copolymer, and - the weight proportion of the flexible blocks is of from 40 to 85% by weight relative to the total weight of the copolymer, the melting point of the copolymer of the invention is equal to or higher than 80°C, preferably higher than 80°C. The present invention concerns a membrane for gas separation, comprising the copolymer and its preparation process.