A linear or branched aliphatic or cycloaliphatic, acetylenic polyamide, characterised in that - said acetylenic polyamide is provided with at least one acetylenic carbon-carbon triple bond, derived from at least one acetylenic compound having said at least one acetylenic carbon-carbon triple bond; - said acetylenic compound is ethynyl o -phthalic anhydride, methylethynyl o- phthalic anhydride, phenylethynyl o -phthalic anhydride, naphthyl ethynyl o -phthalic anhydride, ethynyl isophthalic acid, methylethynyl isophthalic acid, phenylethynyl isophthalic acid, naphthyl ethynyl isophthalic acid, ethynyl terephthalic acid, methylethynyl terephthalic acid, phenylethynyl terephthalic acid, naphthyl ethynyl terephthalic acid, ethynyl benzoic acid, methylethynyl benzoic acid, phenylethynyl benzoic, naphthyl ethynyl benzoic acid, ethynyl adipic acid, methylethynyl adipic acid, phenylethynyl adipic acid, naphthyl ethynyl adipic, ethynyl azaleic acid, methylethynyl azaleic acid, phenylethynyl azaleic acid, naphthyl ethynyl azaleic, ethynyl sebacic acid, methylethynyl sebacic acid, phenylethynyl sebacic acid, naphthyl ethynyl sebacic, ethynyl 2,5-furandicarboxylic acid, methylethynyl 2,5-furandicarboxylic acid, phenyl ethynyl 2,5-furandicarboxylic acid, naphthyl ethynyl 2,5-furandicarboxylic acid and/or a corresponding acid halide or alkyl ester; and - that said acetylenic polyamide comprises monomer units derived from at least one linear or branched aliphatic or cycloaliphatic di, tri or polyfunctional amine; and monomer units derived from at least one linear or branched aliphatic or cycloaliphatic di, tri or polyfunctional carboxylic acid or anhydride or a corresponding acid halide or alkyl ester; or - that said acetylenic polyamide comprises monomer units derived from at least one aliphatic or cycloaliphatic aminoacid and/or at least one lactam. - said acetylenic polyamide is provided with at least one acetylenic carbon-carbon triple bond, derived from at least one acetylenic compound having said at least one acetylenic carbon-carbon triple bond; - said acetylenic compound is ethynyl o -phthalic anhydride, methylethynyl o- phthalic anhydride, phenylethynyl o -phthalic anhydride, naphthyl ethynyl o -phthalic anhydride, ethynyl isophthalic acid, methylethynyl isophthalic acid, phenylethynyl isophthalic acid, naphthyl ethynyl isophthalic acid, ethynyl terephthalic acid, methylethynyl terephthalic acid, phenylethynyl terephthalic acid, naphthyl ethynyl terephthalic acid, ethynyl benzoic acid, methylethynyl benzoic acid, phenylethynyl benzoic, naphthyl ethynyl benzoic acid, ethynyl adipic acid, methylethynyl adipic acid, phenylethynyl adipic acid, naphthyl ethynyl adipic, ethynyl azaleic acid, methylethynyl azaleic acid, phenylethynyl azaleic acid, naphthyl ethynyl azaleic, ethynyl sebacic acid, methylethynyl sebacic acid, phenylethynyl sebacic acid, naphthyl ethynyl sebacic, ethynyl 2,5-furandicarboxylic acid, methylethynyl 2,5-furandicarboxylic acid, phenyl ethynyl 2,5-furandicarboxylic acid, naphthyl ethynyl 2,5-furandicarboxylic acid and/or a corresponding acid halide or alkyl ester; and - that said acetylenic polyamide comprises monomer units derived from at least one linear or branched aliphatic or cycloaliphatic di, tri or polyfunctional amine; and monomer units derived from at least one linear or branched aliphatic or cycloaliphatic di, tri or polyfunctional carboxylic acid or anhydride or a corresponding acid halide or alkyl ester; or - that said acetylenic polyamide comprises monomer units derived from at least one aliphatic or cycloaliphatic aminoacid and/or at least one lactam.