Compositions comprising a cyclic imide unit-containing first polymer and a second polymer different from the first polymer, and the molded compositions obtained

The 2nd polymer comprises 2,4-diamino-1,3,5-triazine (I) side group-contg. monomer units in cyclic imide unit/2nd monomer mol. ratio 0.1-10.0. Both polymers may contain an identical comonomer, e.g., styrene and/or a-methylstyrene. These compns. are miscible with other styrene-contg. polymers, e.g., ABS and SAN polymers, and SBR, are resistant to high temps., and have high rigidity, good flow, and low shrinkage. A mixt. consisting of equal amts. og styrene-maleimide copolymer (prepd. from styrene-maleic anhydride copolymer and urea) and triazine-modified acrylonitrile-styrene copolymer was extruded to give a mixt. having glass transition temp. 170 Deg , rigidity (Emod) 3.0 Gpa, and impact strength (Izod) 1.5, vs. 198 and 154, 3.3 and 1.8, and 2.0 and 7.8, resp. for the 1st and 2nd copolymer individually