Inertial Confinement Fusion experiments are conducted in polymer capsule in which nuclear products are located. In order to vary mechanical properties of polyimide various polyimide blends and copolymers were synthesized and compared. Polyimide blends were obtained by mixing different poly(amic acid) solutions. Dianhydride and various diamines were directly mixed to form a prepolymer in solution. Young’s modulus and coefficient of thermal expansion were measured for the different polyimide specimens. It was shown that mechanical properties of polyimide strongly depend on the composition. The effect of poly(amid acid) preparation process (blends or copolymers) is also discussed.