Polymeric material suitable for making ammunition cartridge casings

A blend comprising a polyphenylsulfone and a rigid-rod polyphenylene copolymer, wherein

• a room temperature notched Izod impact strength of the polyphenylsulfone is greater than about 10 ft-lb/in, as measured by ASTM D256-00 and
• a ratio of notched Izod impact strength at room temperature to notched Izod impact strength at about −40° C. of the polyphenylsulfone is less than about 4;
• and
• the rigid-rod polyphenylene copolymer is a copolymer of formula (1):
• (—Ar—/—Y—)n (1)
• wherein
• n is an integer of 4 or larger,
• a content of —Ar— in the rigid-rod copolymer is at least 0.1 mol %, and
• —Ar— consists of arylene repeat units of formula (2) and formula (3):
• a number average of the arylene repeat units (2) and (3) of —Ar— is greater than 4,
• a number average of para-arylene repeat units in formula (3) is between 1 and about 8;
• a number average of meta-arylene repeat units in formula (2) is greater than 1;
• x of each repeating phenylene unit of formula (2) and formula (3) is independently an integer from 0 to 4, with the proviso that at least 1 of every 100 repeat units has a pendent side group A;
• and
• A of each phenylene unit is independently selected from the group consisting of —F, —CN, —CHO, —COR, —CR═NR′, —OR, —SR, —SO2R, —OCOR, —CO2R, —NRR′, —N═CRR′, —NRCOR′, —CONRR′, and R, wherein R and R′ are each independently selected from the group consisting of H, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl and substituted heteroaryl, and optionally R and R′ if present together may form a bridging group;
• Y is nil or at least one divalent group selected from the group consisting of —Z—, —Z-Ph-, and -Ph-Z-Ph-, wherein Z is a divalent group selected from the group consisting of —O—, —S—, —NR—, —O(CO)—, —O(CO2)—, —(CO)NH(CO)—, —NR(CO)—, phthalimide, pyromellitimide, —CO—, —SO—, —SO2—, —P(O)R—, —CH2—, —CF2—, and —CRR′— and wherein Ph is ortho, meta or para-phenylene.