A polyamide polymer blend comprising: - 5 wt.% to 65 wt.% of a sulfonated polyamide polymer; - 5 wt.% to 50 wt.% of a semi-aromatic polyamide polymer; and - 20 wt.% to 70 wt.% of a reinforcing filler; wherein - the sulfonated polyamide polymer comprises recurring units (R PA1) and (R PA2), wherein recurring unit (R PA1) is represented by the following formula: recurring unit (R PA2) is represented by a formula selected from the following group of formulae: and wherein - R 1 to R 6, at each location, and R 7 to R 9 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - M is either H, Li, Na or K, preferably either Li or Na; - n 1 and n 3 are independently selected integers from 4 to 12, preferably from 4 to 10; and - n 2 is an integer from 4 to 12, preferably from 5 to 12; and - the semi-aromatic polyamide polymer comprises a recurring unit (R PA3) that is represented by a formula selected from the following group of formulae: wherein - R 11 and R 12, at each location, and R 13 to R 20 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - n 4 is an integer from 4 to 12, preferably from 4 to 10; and - n 5 is an integer from 4 to 12, preferably from 5 to 12. - 5 wt.% to 65 wt.% of a sulfonated polyamide polymer; - 5 wt.% to 50 wt.% of a semi-aromatic polyamide polymer; and - 20 wt.% to 70 wt.% of a reinforcing filler; - the sulfonated polyamide polymer comprises recurring units (R PA1) and (R PA2), wherein recurring unit (R PA1) is represented by the following formula: recurring unit (R PA2) is represented by a formula selected from the following group of formulae: and wherein - R 1 to R 6, at each location, and R 7 to R 9 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - M is either H, Li, Na or K, preferably either Li or Na; - n 1 and n 3 are independently selected integers from 4 to 12, preferably from 4 to 10; and - n 2 is an integer from 4 to 12, preferably from 5 to 12; and - R 1 to R 6, at each location, and R 7 to R 9 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - M is either H, Li, Na or K, preferably either Li or Na; - n 1 and n 3 are independently selected integers from 4 to 12, preferably from 4 to 10; and - n 2 is an integer from 4 to 12, preferably from 5 to 12; and - the semi-aromatic polyamide polymer comprises a recurring unit (R PA3) that is represented by a formula selected from the following group of formulae: wherein - R 11 and R 12, at each location, and R 13 to R 20 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - n 4 is an integer from 4 to 12, preferably from 4 to 10; and - n 5 is an integer from 4 to 12, preferably from 5 to 12. - R 11 and R 12, at each location, and R 13 to R 20 are independently selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; - n 4 is an integer from 4 to 12, preferably from 4 to 10; and - n 5 is an integer from 4 to 12, preferably from 5 to 12.