A foam material having one glass transition temperature (Tg), as measured by differential scanning calorimetry and made from an immiscible composition having at least two glass transition temperatures (Tg) [composition, herein after] by an extrusion process wherein said composition comprises: (i) at least one polyarylene polymer, wherein more than 50 % by moles (moles %) of the recurring units of said polymer are recurring units consisting of an arylene group, wherein said arylene group is a hydrocarbon divalent group consisting of one core [core, herein after] composed of one benzene ring or of a plurality of benzene rings fused together by sharing two or more neighboring ring carbon atoms, said benzene ring being optionally substituted, wherein each of said arylene group is bound to two other arylene groups of neighboring recurring units through a first C-C bond and a second C-C bond, wherein at least 20 moles % of recurring units are kink-forming arylene units (R1-b) [arylene R1-b units hereafter,], the remainder being rigid rod-forming arylene units (R1-a) [arylene R1-a units hereafter] different from arylene R1-b units, wherein in said arylene R1-a units the bond and the bond are co-linear and anti-parallel towards each other, said polymer being present in composition in an amount of below 75 % by weight (wt. %) and above 10 wt. % based on the total wt. % of polymer and (PPSU) polymer, and (ii) at least one polyphenylsulfone polymer [(PPSU) polymer, herein after], wherein more than 50 % by moles of the recurring units of said (PPSU) polymer are recurring units (R PPSU) of formula, herein below: said (PPSU) polymer being present in composition in an amount of below 90 wt. % and above 25 wt. % of based on the total wt. % of polyarylene polymer and (PPSU) polymer. (i) at least one polyarylene polymer, wherein more than 50 % by moles (moles %) of the recurring units of said polymer are recurring units consisting of an arylene group, wherein said arylene group is a hydrocarbon divalent group consisting of one core [core, herein after] composed of one benzene ring or of a plurality of benzene rings fused together by sharing two or more neighboring ring carbon atoms, said benzene ring being optionally substituted, wherein each of said arylene group is bound to two other arylene groups of neighboring recurring units through a first C-C bond and a second C-C bond, wherein at least 20 moles % of recurring units are kink-forming arylene units (R1-b) [arylene R1-b units hereafter,], the remainder being rigid rod-forming arylene units (R1-a) [arylene R1-a units hereafter] different from arylene R1-b units, wherein in said arylene R1-a units the bond and the bond are co-linear and anti-parallel towards each other, said polymer being present in composition in an amount of below 75 % by weight (wt. %) and above 10 wt. % based on the total wt. % of polymer and (PPSU) polymer, and (ii) at least one polyphenylsulfone polymer [(PPSU) polymer, herein after], wherein more than 50 % by moles of the recurring units of said (PPSU) polymer are recurring units (R PPSU) of formula, herein below: said (PPSU) polymer being present in composition in an amount of below 90 wt. % and above 25 wt. % of based on the total wt. % of polyarylene polymer and (PPSU) polymer.